My Po300 thread

[Crazyjoker77]

Okay i think ive read pretty much every post on the internet about Po300 but still have not come to any conclusions on what is causing mine. My mods are in my profile.

The Symtoms

-when i start the car up first thing in the morning it fires up right away but will stall out completely after a lil while (30sec to 2min)(as well it idles high and pull about 18"hg which seems normal.)

-when im driving it it will backfire and stall out. the wierd thing is that it is completely random when it happens although tends to happen more at steady state cruising.(if the car is still in gear it will start up right away and act like nothing happened if the clutch is in when it happens the car stalls out completely and i either have to pop the clutch or crank the starter. and she fires right back up.)

-at idle it usually idles right at 850rpm but sometimes will drop to 750-790 and my gauge will read 15"hg as well the motor sounds very lopey as if i had cams. If the car is idleing at 850 and i step on the brakes hard my vacuum will suck down to 15" and the idle will drop down and stay there till i rev it alittle bit then it will resume its proper idle.(although it could possible be the other way around my rpms fall causing low vacuum instead of my vacuum causing low idle?)

-as well the cars performance is very inconsistent sometimes it will pull very hard at the slighest throttle other times it feels as if timing is being retarded. also the rpm at which my turbo spools also seems pretty inconsistent.

What I've done

-new plugs ngk br7es gapped at .28
-wires are new oem with less than 10k on them
-coil packs all test within spec (primary and secondary)
-pulled ecu to check for leaky caps
-checked coils on ISC

Other notes
-mabey every 40 or so backfires the code Po300 will pop up i clear it immediatly with my logger.

-I also sometimes will get the code for my FP solenoid if i turn my car off for 5min or so then start it back up but the thing is i have the solenoid bypasses and just have in sitting on the firewall with the connector still on(although ive only gotten this code once since ive bypassed it)

-and yesturday while i was letting my car warm up idleing i came back and had a code for misfire cylinder 3. (first time ever seeing that code and hasnt come back since)


i did do a boost leak test from my lower IC pipe. During which i found some intersting things.

-First off my GM mas was leaking slightly from between the metal housing and the plastic case on the upstream side.(not audible but when sprayed with soapy water it bubbled)

-i had another leak from the top of my blitz BOV from the adjustment screw(which i assume is a vacuum leak as well since its on top of the diaphram) I replaced mine with a friends brand new blitz and his leaks just as bad as mine does...

-the third leak is from my FPR right from where the top half meets the bottom half(again not audible but forms bubbles)

even with these leaks my test performed good i would pressurize it to 25psi
it would bleed down to 18 in about 12sec
bleed down to 10 in another 12-15seconds
then it would hold 9-10psi indefinatly...
which i believe are fairly good results especially considering i still have some small leaks.


-I've ordered a few things that im waiting on arriving which include a wideband o2, a aeromotive FPR with gauge and a egr blockoff so i can remove most of the vacuum lines in my engine bay.

Questions

1)Im going to check the timing is all i have to do is pull the upper cover off and turn the motor till the timing marks line up or do i also have to remove the lower cover and check to make sure the crank is lined up as well?

 

[crimsondragon]

Maybe you mixed up the wires on the cylinder. You should check to make sure that each spark plug wire goes to the right cylinder and likewise to the coilpack.

 

[super97gst]

Have you read through mine and bboyalan's threads?? I'm guessing you have since you said you have read all the PO300 threads. First off your timing is not gonna be off. Thats a for sure thing. If the timing was off, ie ( if the t-belt jumped a tooth) the car wouldn't run right period. Since you are getting symptoms when you push the clutch in your best bet at the moment is gonna be test the CPS. Usually when a CPS starts going out it will present problems when the clutch is depressed. This will also cause the po300 code to be thrown. If you have read in entirity our threads you know what has and hasn't worked.

You said you are getting a po303. You need to perform a compression check on the car, just to make sure you don't have a dead cylinder. Your boost leak results look good. It's highly unlikely that is your problem. You need to start running through all the tests that we performed in our threads. There are a lot of them. You need to test the TPS, CAS, CPS, MDP sensor, the MAS can also cause these problems. Oh, and just because your ecu didn't look like it had leaky caps doesn't mean the ecu isn't the root of your po300, that also doesn't mean it is. The only thing you can do as far as the ecu is test everything else first, if everything tests good you have a bad ecu. Keep us posted and I'll sure try to help you along as well as I can.

 

[Crazyjoker77]

Have you read through mine and bboyalan's threads?? I'm guessing you have since you said you have read all the PO300 threads. First off your timing is not gonna be off. Thats a for sure thing. If the timing was off, ie ( if the t-belt jumped a tooth) the car wouldn't run right period. Since you are getting symptoms when you push the clutch in your best bet at the moment is gonna be test the CPS. Usually when a CPS starts going out it will present problems when the clutch is depressed. This will also cause the po300 code to be thrown. If you have read in entirity our threads you know what has and hasn't worked.

You said you are getting a po303. You need to perform a compression check on the car, just to make sure you don't have a dead cylinder. Your boost leak results look good. It's highly unlikely that is your problem. You need to start running through all the tests that we performed in our threads. There are a lot of them. You need to test the TPS, CAS, CPS, MDP sensor, the MAS can also cause these problems. Oh, and just because your ecu didn't look like it had leaky caps doesn't mean the ecu isn't the root of your po300, that also doesn't mean it is. The only thing you can do as far as the ecu is test everything else first, if everything tests good you have a bad ecu. Keep us posted and I'll sure try to help you along as well as I can.

sory i guess i should of said i perform a comp check i dont remeber the exact numbers but it was well within spec as its a fresh motor with less than 15000km on it.

As well i did test the tps with a ohmmetter when i did my shaft seals and again everything was in spec (as well i can see it read properly on my logger as well)

Its interesting that you brought up the CPS as i did have some issues with that awhile ago and a shop replaced it. As far as testing the CPS and CAS im assuming i have to hook up a oscilloscope and look at the wave pattern to test them?

How would i go about testing the MDP sensor i know its located on the top of the intake manifold.

I still have yet to test my power transitor.

So far i'm kind of leaning towards a sticky EGR valve so ill wait til my plate comes in and see if that helps any.

 

[super97gst]

http://www.dsmtuners.com/forums/problem-diagnosis/291862-my-car-has-gone-skits.html

There's the link to a thread where I discussed how to test the MDP sensor.

The CAS and CPS can be tested without an oscilloscope. Unplug the connector, there will be 3 pins on each sensor. Those 3 pins are power supply, ground and signal output.

The first thing you need to do is check that the sensor is getting voltage from the ecu. With the key on, use a multimeter and test that the power supply pin on the harness side is getting voltage. You should get 12 volts, if you don't then you have a broken wire or short. Next attach the leads on your multimeter to the other 2 leads. Positive to the signal pin and ground to ground. Also, the plug wires need to be disconnected from the coil during this test. With your leads attached have someone crank the car over, you should get .4 to 3 volts. The last test is just for the ground pin. Just test resistance between the ground pin and ground on the motor. It should test less than 2 ohms. You can test both the CAS and the CPS with this same test. The only difference in the tests of the 2 sensors are the position of the pins. On the CAS pin 1 is power supply, 2 is ground and 3 is signal. The CPS pins are: 1 signal, 2 power supply and 3 is ground.

 

[ekanddsm]

I would say wait a moment on swapping parts and double checking other parts.
Take the car out for a drive and MAKE the engine light come on/ it will flash while the code is happening.

Pull up the p0300 and read off some data from the freeze frame and find out why it is misfiring.
Faulty Mas readings, low or high comression, ignition misfire, etc etc etc.
The freeze frame data will point you in a good direction.
Look at fuel trims% both short and long, Mas reading, Baro, O2 value. Your car is not igniting, or compressing, or squirting fuel, or getting enough air.

Boost leaks need to be fixed you know that, But you can get it to hold 25 psi longer.

The problem is right there but we need to know what its sympton are.

The better question is; How is it not firing?

 

[Artago]

Hey CrazyJoker.

Let me be the first one to welcome you to the wonderful world of P0300's.

Ok, lets get down to business.

I had a MDP problem which threw a P1400. I replaced the MDP and the code went away. Didn't solve my P0300.

I swapped my ECU (used a 97 ecu). Didn't fix my P0300.

Ok. Now down to the symptoms.

I also, have the P1105 code (FP solenoid). I ordered a new one from JNZ. It's not here yet, but once I get it I'll post back. This guy only appeared after my ECU swap.

I also have some high idle but only when the car is warm. Around 1.5k-2.2k RPM but when I hit the throttle (in neutral) and send the TPS to 100% and release, the idle will drop down to around 1k-1.5k RPM. Try this out and report back if your idle drops back down.

I also have some funny brake issue. Sometimes, when the car is cold, the brake will seem unresponsive and brake pedal is soft. It's scares the $hit out of me because I hit the brakes and not much happens. It never does this warm.

I also have some funny clutch issues. Sometimes, randomly, it will go soft on me. Or other times, the point at which it catches goes REALLY low. Like at the floor.

I also have an unknown boost/vac leak somewhere under the Intake manifold. I can hear it but can't find it. I plan to fix this leak this weekend. It has been suggested that the leak is coming from the brake booster lines or EGR lines.

I've also had a cylinder misfire other than random. Except for me it's cylinder 2 and it ONLY appeared after the ECU swap. The ECU was a 97 so I had to swap the plug wires so wire 2 is now wire 3. So I don't know if the misfire was detected in cly #2 or #3. I suspect #3 because of the wire swap. Don't know for sure though. EDIT: This code only appeared after the ECU swap.

Regarding the EGR valve. I've also suspected this guy for a while. I plan to either pull him out and clean him or just block him off entirely.

Uh... I think that's it. If I remember anything else useful I'll post.

Oh, and make sure you post back with progress regularly so we can all figure this out together.

Good luck,

Tom

PS: How is your motor from Overbore working out? I got one too.

 

[Artago]

Maybe you mixed up the wires on the cylinder. You should check to make sure that each spark plug wire goes to the right cylinder and likewise to the coilpack.

Car would not even start if you mixed up the wires. At least mine didn't when I mixed them up.

 

[crimsondragon]

I would think it's possible to just mix two of them up so it's like having two dead cylinders and two working ones. I don't know, but I could be wrong.

 

[Artago]

I would think it's possible to just mix two of them up so it's like having two dead cylinders and two working ones. I don't know, but I could be wrong.

Yup. The car will turn over but instantly die.

 

[Crazyjoker77]

Hey CrazyJoker.

Let me be the first one to welcome you to the wonderful world of P0300's.

Ok, lets get down to business.

I had a MDP problem which threw a P1400. I replaced the MDP and the code went away. Didn't solve my P0300.

I swapped my ECU (used a 97 ecu). Didn't fix my P0300.

Ok. Now down to the symptoms.

I also, have the P1105 code (FP solenoid). I ordered a new one from JNZ. It's not here yet, but once I get it I'll post back. This guy only appeared after my ECU swap.

I also have some high idle but only when the car is warm. Around 1.5k-2.2k RPM but when I hit the throttle (in neutral) and send the TPS to 100% and release, the idle will drop down to around 1k-1.5k RPM. Try this out and report back if your idle drops back down.

I also have some funny brake issue. Sometimes, when the car is cold, the brake will seem unresponsive and brake pedal is soft. It's scares the $hit out of me because I hit the brakes and not much happens. It never does this warm.

I also have some funny clutch issues. Sometimes, randomly, it will go soft on me. Or other times, the point at which it catches goes REALLY low. Like at the floor.

I also have an unknown boost/vac leak somewhere under the Intake manifold. I can hear it but can't find it. I plan to fix this leak this weekend. It has been suggested that the leak is coming from the brake booster lines or EGR lines.

I've also had a cylinder misfire other than random. Except for me it's cylinder 2 and it ONLY appeared after the ECU swap. The ECU was a 97 so I had to swap the plug wires so wire 2 is now wire 3. So I don't know if the misfire was detected in cly #2 or #3. I suspect #3 because of the wire swap. Don't know for sure though. EDIT: This code only appeared after the ECU swap.

Regarding the EGR valve. I've also suspected this guy for a while. I plan to either pull him out and clean him or just block him off entirely.

Uh... I think that's it. If I remember anything else useful I'll post.

Oh, and make sure you post back with progress regularly so we can all figure this out together.

Good luck,

Tom

PS: How is your motor from Overbore working out? I got one too.

GLad to see this thread is getting some responses. I have driven the car for the past 3 days now (roughly 350km) it only backfired once yesturday but was a bi*** to start this morning (stalling out about 6 times) as well it was good for most of the day but as i was leaving my friends house it backfired probably 5 times on my way home. No codes have popped up at all either?

It seems over the past couple days the backfires have become less severe and less frequent as well the car has stopped pulling odd vacuum readings and the idle will mostly stay where it is suppose to sometimes being high (usually when i have the heater on) As well it barely ever stalls out anymore when it backfires. 3 days ago it was at the point i would barely make it 3 blocks without a backfire that soudned like a gunshot usually followed by it stalling. now i can go hours without and when it does its more of a pop (or a couple)

My fuel trims are dead on never going past -10 or 10 although i am adding alot more fuel than i believe i should be. I have 650cc injectors which i set the maf-t to compensate for so my safc setting should be relativley around 0 but my 1000 point is at +24% and gradually scales down to about 14% by 5k(low tables) high tables are all around 12% if i move the points my fuel trims go off from 0.(this leads me to believe that i still have a vacuum leak as unmetered air is bypassing the mas causing it to go lean which i band-aid with the fuel controller...or i may be thinking to deep into it)

regardless my parts are gonna be here may 6th ill finish testing the rest of my sensors before then. install my wideband first and go for a ride and see what my ratios are at and get a little better idea to whats happening when these backfires are happening. I then am gonna block off the EGR and cap all the vacuum lines eliminating vac leaks and the sticky egr. THen if that doesnt help i guess i will install the FPR and guage and see whats happening with the fuel pressure or if that air leak on my fpr is the cause of my issues. Seems like a logical series of steps to take.

For now ive turned the boost down to 15psi(wastegate pressure) I wetn full throttle to see how it is behaving at full boost and it seemed fine except i believe it was pulling timing 6k up( i forgot to log the run)

it seems my issue is not as serious as most of the other threads but its still very annoying.

 

[Crazyjoker77]

As for my motor from overbore ive had no issues with the motor itself but my dealings with mark at overbore are not great at all. He has yet to refund my core charge took 7months for me to recieve my motor which he had a new excuse for every week that i called him. And i believe he never put the revised lifters in the motor like i requested(and payed for) as i still have horrible lifter tick at idle(ill find out when i pull the VC off)

 

[Artago]

As for my motor from overbore ive had no issues with the motor itself but my dealings with mark at overbore are not great at all. He has yet to refund my core charge took 7months for me to recieve my motor which he had a new excuse for every week that i called him. And i believe he never put the revised lifters in the motor like i requested(and payed for) as i still have horrible lifter tick at idle(ill find out when i pull the VC off)

Yeah let me know about the lifters. The guy seems shady which is why I never returned me core. But let me know if he screwed you at all.

Tom

 

[super97gst]

Yup. The car will turn over but instantly die.

And backfire like a Biaatch.

Btw, you sound like you are running quite lean. I believe a lot of the a/f problems associated with the PO300's is originating in the MAS. I will know in a couple of days as my MAS and ECU get here. The MAS contains the intake air temp sensor and a barometric pressure sensor. A lot of PO300's seem to cause problems at different ambient air temps. This is most likely the IAT sensor within the MAS. It might be worth a shot to test your MAS while your at it. Since you are definitely getting misses while the clutch is depressed I would suggest testing the CPS like I said before. Unlike stated above the code's not gonna just pop up and tell you exactly what's wrong. Things have to be tested and replaced. As quick as my parts get here I'll post back and let you know what happens with my PO300.

 

[Artago]

And backfire like a Biaatch.

Btw, you sound like you are running quite lean. I believe a lot of the a/f problems associated with the PO300's is originating in the MAS. I will know in a couple of days as my MAS and ECU get here. The MAS contains the intake air temp sensor and a barometric pressure sensor. A lot of PO300's seem to cause problems at different ambient air temps. This is most likely the IAT sensor within the MAS. It might be worth a shot to test your MAS while your at it. Since you are definitely getting misses while the clutch is depressed I would suggest testing the CPS like I said before. Unlike stated above the code's not gonna just pop up and tell you exactly what's wrong. Things have to be tested and replaced. As quick as my parts get here I'll post back and let you know what happens with my PO300.

Interesting bit about the intake temps. I log mine and they are about 90 driving 120 idle, and it's cold over here like around 40-45 outside. Is this normal? Also, my MAS reads 0.18 Lbs/min when the engine is OFF. That, I'm assuming is NOT normal.

Tom

 

[PieEyedPiper]

How much boost are you running?
Why are you adding 24% more fuel with the safc?

Maybe it's possible that your Maf-t tune is such that you need to compensate for it by adding that much fuel?
You might entertain the thought of zeroing out your Maf-t and starting from scratch with the safc. I can't think of any reasonable explanation for you to have to add 24% more fuel with 650's.

Using two tuning devices in tandem is a recipe for over compensation or even a complete misinterpretation of how much fuel you think your car needs.

backfires + adding 24% more fuel = too much of a coincidence, in my opinion.

 

[PieEyedPiper]

Interesting bit about the intake temps. I log mine and they are about 90 driving 120 idle, and it's cold over here like around 40-45 outside. Is this normal? Also, my MAS reads 0.18 Lbs/min when the engine is OFF. That, I'm assuming is NOT normal.

Tom

Those are the same temps I see right now, usually lower than 90 though if I'm just cruising around town. I'm working on a cold air box or heatshield idea currently. Is that pocketlogger giving you those readings for your MAS?

Unless I'm mistaken, I believe that pocketlogger uses a formula to derive the lbs/min readout and is not always the most accurate, though usually gives you a good idea.
If thats the case here, 1.8+- crank hp might be close enough to zero for the intended purpose.

 

[Artago]

Those are the same temps I see right now, usually lower than 90 though if I'm just cruising around town. I'm working on a cold air box or heatshield idea currently. Is that pocketlogger giving you those readings for your MAS?

Unless I'm mistaken, I believe that pocketlogger uses a formula to derive the lbs/min readout and is not always the most accurate, though usually gives you a good idea.
If thats the case here, 1.8+- crank hp might be close enough to zero for the intended purpose.

Yeah I got that reading from the pocketlogger. Yeah my heat shields (yeah I have more than one ) helped with that. I just wanted to make sure.

If thats the case here, 1.8+- crank hp might be close enough to zero for the intended purpose.

I'm not sure what you mean by this. Can you explain?

Thanks,

Tom

PS: Welcome to yet another P0300 thread.

 

[Crazyjoker77]

How much boost are you running?
Why are you adding 24% more fuel with the safc?

Maybe it's possible that your Maf-t tune is such that you need to compensate for it by adding that much fuel?
You might entertain the thought of zeroing out your Maf-t and starting from scratch with the safc. I can't think of any reasonable explanation for you to have to add 24% more fuel with 650's.

Using two tuning devices in tandem is a recipe for over compensation or even a complete misinterpretation of how much fuel you think your car needs.

backfires + adding 24% more fuel = too much of a coincidence, in my opinion.

I'm currently running 15psi of boost till i get this issue resolved but before that either running 21psi or 18psi each with there own tune on the safc.(im currently using the 18psi high throttle tune)

The maf-t Is set up for properly i double checked all the switches its set for 650s all the other knobs are zero'd out(so its just pulling about 20% fuel throughout the whole rpm range. If i change the SAFC setting away from 24% my fuel trims move off from 0. (as well i ran my setup like this for well over a year with no issues)

again im kinda waiting on the wideband to get more insight on this...

as for intake temps and the such affecting the GM unit i quote this from another thread

Common guys. It's not to difficult to understand.

The stock MAF measures 3 things
AIR VOLUME / AIR TEMP / AIR BAROMETRIC PRESSURE

Then the ECU uses (PV/T = MASS) to calculate MASS.

The GMAF measure only 1 thing. It measures MASS directly. So when the ECU receives it's signal from the GMAF it is measurement of MASS and not Volume. Therefore the Translator MUST hold barometric pressure and air temp constant so that the (PV/T =M) calculation is not corrupted. We already have M directly from the GMAF.

So anyone who says that air temperature affects the MAFT reading does not understand how it works. The MAFT takes into account high temperature and low temperatures by calculating MASS, not volume.

 

[super97gst]

I forgot you were running a blow through setup. That is exactly right that ambient air temps do not affect a GM MAS. Have you tried testing any of your sensor yet?? The MDP sensor is not gonna affect everything that you are having go wrong. The MDP sensor will usually only cause idle problems if it's going out. It produces most of its voltage signal during idle. Plus it's just measuring IM vaccuum so that usually just affects voltage. I still think your CPS would be a good place to look into.

 

[PieEyedPiper]

Yeah I got that reading from the pocketlogger. Yeah my heat shields (yeah I have more than one ) helped with that. I just wanted to make sure.



I'm not sure what you mean by this. Can you explain?

Thanks,

Tom

PS: Welcome to yet another P0300 thread.

I meant to describe the inaccuracy of pocketloggers' lbs/min calculation and that when viewing that particular parameter, with the ignition on but engine off, it might be possible the value produced is a low number such as .18lbs/min, which, for all effective means of that potentially inaccurate representation of the true value, it is close enough to zero to be interpreted as no airflow by the tuner. After all, the engine is off.

It was just a scenario that I think not too unlikely even if it may, in actuality, indicate your air metering system is uncalibrated in some fashion.

Thanks for the invite. 'tis the P0300 season it seems..

 

[Crazyjoker77]

little update so far I've been driving the car as much as possible lately and really not much has changed at all. My wideband and AFPR came in. the wideband really doesn't show anything out of the ordinary other than when it backfires or tries to die out it pegs rich...

I've yet to install the EGR blockoff and eliminate a bunch of vacuum lines.

Tested my MDP sensor and it checked out...

gonna try the egr plate this weekend and see if it helps anything as well i have some new wires comming sometime next week although im almost positive they are still good as they only have about 15,000km.

This problem is gettin very frustrating in the fact that its just that completly random and the only time it doesnt happen is when i'm deaccelerating. and the fact that i can go from not having any issues for days(other than the stalling on cold starts) then the car barely being drivable backfiring and bogging every 5-10min.

I'm at the point where i've pretty much tested everything and just gotta start throwing parts at it till everything is new....

 

[Artago]

Ok I have a request for everyone fighting the P0300.

I was doing a boost leak test and I pressurized the system and started spraying everything with soapy water to look for bubbles. Well I found bubbles coming out of the strangest place. I found bubbles coming from the fuel pressure regulator (not the solenoid). And I don't mean from the seal where it connects to the fuel line. The bubbles were coming from the top "hat" portion where the top meets the bottom. (I'll take pictures next time I do a BLT)

So my request is: To those of you with the P0300. Can you do a boost leak test and spray the fuel pressure regulator with soapy water and check for bubbles? I'm curious if anyone else has this vac/boost leak and if it has anything to do with the P0300.

Thanks,

Tom

 

[Crazyjoker77]

Ok I have a request for everyone fighting the P0300.

I was doing a boost leak test and I pressurized the system and started spraying everything with soapy water to look for bubbles. Well I found bubbles coming out of the strangest place. I found bubbles coming from the fuel pressure regulator (not the solenoid). And I don't mean from the seal where it connects to the fuel line. The bubbles were coming from the top "hat" portion where the top meets the bottom. (I'll take pictures next time I do a BLT)

So my request is: To those of you with the P0300. Can you do a boost leak test and spray the fuel pressure regulator with soapy water and check for bubbles? I'm curious if anyone else has this vac/boost leak and if it has anything to do with the P0300.

Thanks,

Tom

actually i started a thread about this when i first started combating this problem and the reason i purchased the AFPR. http://www.dsmtuners.com/forums/newbie-forum/292277-blt-results-leaking-fpr.html

i've been driving with the new non leaky aeromotive unit for about a week now and it did absolutely nothing to help the problem.

 

[Crazyjoker77]

well a little update been driving the car and it actually seemed to be getting better to the point where it would never backfire or stall out anymore(except if i tried to drive the motor cold)

BUT yesterday I was cruising and got on it pretty hard in first gear to get ahead of a truck from a set of lights so i could turn left at the next set of lights a half block down. got to the set of lights and as i went to take off the motor just shut down. I attempted to start it for probably 3mins just cranking sometimes it would kinda fire up but die out almost immediately. just as the light turned yellow the car fired up and i pulled out of the intersection parked immediately and left the car running and poped the hood.

As soon as i got out of my car i smelled a rather strong odour that smelled very much like burnt clutch (although it could of very well been the diesle fumes from the truck that stomped on it since i pulled in front of him then sat in the intersection for 3min trying to start my car) the smell dissipated rather quickly. while quickly inspecting it on the side of the road nothing looked out of the ordinary nor did it make any funny sounds.

Although at the time it seemed as if my harmonic balancer/crank pulley had some play in it. I babied the car home and had no issues on the drive there which was about 5km. got it back to my house and looked at the crank pulley from underneath and couldnt notice any play.

Decided to do a oil change on it today and pull off the splash shields so i could get a good look at the harmonic balancer and see if the rubber part has started to seperate. It looked very healthy to me and seemed to have no play in it. The oil came out normal and didnt have anything in it to concern me.

Now im getting very confused as to what the hell is happening with my car...

only things i still have to check are
-Crank position sensor
-Fuel filter
-Tune(somewhat o2 trims are accurate and wideband is reading pretty close to what it should)
-front o2 sensor(while i am getting a reading from it i am doubting the accuracy of it and if this is off my fuel trims will be off and therefore causing my tune to be way off)


only other thing i would like to bring to everyones attention is that i had a issue very similair about 6-7k miles ago where i gunned it down a valley coasted for a little bit in neutral as soon as i put it back in gear and loaded up the engine the engine shut down exactly like it did the other day at the intersection. Except that when it happened going back up the hill i could not get it to start back up and had to have it towed to a shop. The shop found that my crank Sprocket had worn the little notch (keyway) almost 2.5x the size it should of been. I seen the sprocket for myself and it was in horrible condition. this sproket being loose gave it enough play for the backing plate to chew up the crank position sensor. Im just a little concerned that this may be the case again but am a little concerned at what would be causing this sprocket to wear?(hopefully not crankwalk as its a 7bolt motor from overbore.com that ive put less that 20k miles on yet.


Also Artago did you find out anything more about the leaky FPR i noticed you put that post in most of the Po300 threads.

Sorry for the long post but i just want to get this damn car reliable again.