2g Random Misfire Code (no 6bolt)

[PieEyedPiper]

I've made this new thread because I've narrowed my problem down some and the old thread was cluttered.

Problem: Code P0300, (i think?) Random Multiple Cylinder Misfire. When I'm on the HWY, keeping the RPM's steady, my car will eventually throw this CEL and the car will vibrate and stutter like mad.

Temporary Solution: While cruising at around 70-80mph, and I encounter this phenomenon, I take the car out of gear, shut it off, allow the RPM's to hit zero, restart the car, put it back in 5th and carry on my merry way.
This is NOT desireable.

I have new plugs, NGK BPR6ES gapped at .028, I've cleaned my Accel Thundersport wires and attempted to test my coil pack.
I have this diagram, shown to me by another helpful DSMTuners member, http://dsmtuners.com/forums/attachme...1&d=1088544507

I cannot really make sense of it. Too many shadowed testing positions etc.

Plus I can only find two things to test on the coilpack.
The PDOB (poorly drawn offensive bitmap) should hopefully show up somehwere in this thread.

I get ~20Kohm in my voltmeter by testing the two ports on each coil pack. Both packs yield identical results. I cannot find a third port to test.

The car otherwise is running as strong as ever @ 15 PSI with a 1g bov and a MBC connected at the bov line.

Now all I need is some more direction.
Thanks!

 

[Highwayrun]

Temporary Solution: While cruising at around 70-80mph, and I encounter this phenomenon, I take the car out of gear, shut it off, allow the RPM's to hit zero, restart the car, put it back in 5th and carry on my merry way.
This is NOT desireable.

You can also push in the clutch and drop the RPMs to idle to cure the misfire. This is a lot safer.

(I had the same problem a while back, but now very rarely--random misfire in cylinder #4.)

 

[csgsx23]

Okay guys, I had the exact same problem. I had the coil pack checked, new plugs put in and did a full boost leak check, but none of this had any effect. So I took it to my local trusted shop (extreme motorsports) and they replaced the cam angle sensor. Afterwards I drove the car home and it ran like new. No vibrations or and of that sputtering crap. So i would have the cam angle sensor checked out. Good luck.

 

[PieEyedPiper]

You can also push in the clutch and drop the RPMs to idle to cure the misfire. This is a lot safer.

(I had the same problem a while back, but now very rarely--random misfire in cylinder #4.)

I'll have to try that cause yeah it's scary shit coming up to a corner at 75mph and having your steering wheel lock cause your keys are in the off pos.!!!

CAS eh? Could someone explain to me how that would induce a random misfire condition?

 

[Highwayrun]

According to the shop manual, for P0300, P0301, P0302, P0303 and P0304 the following should be checked:
*Ignition coil;
*Ignition power transistor;
*Spark plug;
*Ignition circuit;
*Injector;
*O2 sensor;
*Compression pressure;
*Timing belt;
*Crankshaft position sensor;
*Air intake;
*Fuel pressure; and
*Crankshaft position sensor circuit and connector.

Since your code is P0300, Random Misfire Detected, I'd say you can omit some of the things on the list, such as spark plugs, as they'd give a specific code for the problematic cylinder. (For example, a bad plug in cylinder #2 would give a code of P0302.)

By the way, in a round about way, you're helping me solve my problem too!

 

[olmytsi]

Try resetting your ecu and see if it keeps occuring.
Another thing that i have noticed is that the code is more prone to come back when it is stored in the ecu and hasn't been cleared.

 

[PieEyedPiper]

Try resetting your ecu and see if it keeps occuring.
Another thing that i have noticed is that the code is more prone to come back when it is stored in the ecu and hasn't been cleared.

Your idea reminds me of crossing my fingers when I'm trouble shooting a PC, haha!
It deifnitely keeps happening after I reset the ECU.

Does anyone know how this could be related to me CAS? and is that crank angle? or cam angle?

 

[olmytsi]

Cas usually means cam angle sensor.

 

[marq95gst]

According to the shop manual, for P0300, P0301, P0302, P0303 and P0304 the following should be checked:
*Ignition coil;
*Ignition power transistor;
*Spark plug;
*Ignition circuit;
*Injector;
*O2 sensor;
*Compression pressure;
*Timing belt;
*Crankshaft position sensor;
*Air intake;
*Fuel pressure; and
*Crankshaft position sensor circuit and connector.

Since your code is P0300, Random Misfire Detected, I'd say you can omit some of the things on the list, such as spark plugs, as they'd give a specific code for the problematic cylinder. (For example, a bad plug in cylinder #2 would give a code of P0302.)

By the way, in a round about way, you're helping me solve my problem too!

Mine too!!! I've checked everything on the list except the injectors and compression test (not the cas, but i have a 95..no cas). Cylinder 1 and 2 don't shoot fuel. I have spark though. My ecu is not at fault, as I put another on to check. Ignition supression resistor changed too. This sucks. I can't even use my car.

 

[Highwayrun]

Cylinder 1 and 2 don't shoot fuel. I have spark though.

Swap the 1 & 2 injectors with the 3 & 4 ones. If 3 & 4 shoot fuel while connected to the 1 & 2 harnesses, then clean the dirty 1 & 2 injectors, if they're not burnt out--or buy new ones.

If the 3 & 4 injectors still shoot nothing on the 1 & 2 harnesses, then check the harnesses.

Since the 3 & 4 harnesses are good, you'll know right away if the 1 & 2 injectors are good.

I bet your 1 & 2 injectors are gummed up, or burned out.

 

[PieEyedPiper]

Not sure what that last post is about? is that from a different thread?

Anyways, can anyone tell me more about my CAS? how its related to this issue, and such?

 

[olmytsi]

It could be bad, thats all i can think of.
But if it were bad, the misfire wouldn't be random in my opinion, it would occur constantly. Try finding another one and swapping it.

 

[PieEyedPiper]

Can't hurt I suppose. I just dont wanna be trying things for the hell of it.
Any idea how much these things cost? If it's reasonable I'll just buy a new one.

 

[olmytsi]

No clue what they go for new, but i bet it isn't cheap. However, with the number of 6 bolted 2gs, im sure there are more than a few just laying around in people's garages. I would try doing a classifieds ad and see what happens.

 

[PieEyedPiper]

I realize this is the never ending thread.. but does someone have any further info on testing the coil packs? See first post.

And thanks for the tip, I'll check the classifieds.

 

[DragSourceTsi]

pm me i have one

 

[SFRacingGST]

I can say that the problem my car has is exactly mentioned here. Sometimes injector driver 4 cuts out while driving causing the car to shoot the code P0300 and start to shake. I had Pruven in CT Look at the car for awhile, the replaced everything in the car with a known working part and the car still did this weird problem. They had told me i should try replacing my IAC motor because they would sometimes shorten out while driving and send a signal back to the ecu and shorten out a certain area (in my case it was the 4 injector drive). So i bought a new IAC and had a new "optical" CAS put on. I got the car back only to be driving much better, however i have still gotten the missfire four times in 650 miles. Before these sensors were replaced the car was basically undrivable and now i can drive it with a random miss every once in a while. I have contacted pruven since to get a professional opinion on it and they said that it could be that my ecu substained damage when it was getting shortened out and thats why i get the random miss. I am curious if the person who had his 4th cylinder cutting out if he has fixed it yet??

 

[olmytsi]

I can say that the problem my car has is exactly mentioned here. Sometimes injector driver 4 cuts out while driving causing the car to shoot the code P0300 and start to shake. I had Pruven in CT Look at the car for awhile, the replaced everything in the car with a known working part and the car still did this weird problem. They had told me i should try replacing my IAC motor because they would sometimes shorten out while driving and send a signal back to the ecu and shorten out a certain area (in my case it was the 4 injector drive). So i bought a new IAC and had a new "optical" CAS put on. I got the car back only to be driving much better, however i have still gotten the missfire four times in 650 miles. Before these sensors were replaced the car was basically undrivable and now i can drive it with a random miss every once in a while. I have contacted pruven since to get a professional opinion on it and they said that it could be that my ecu substained damage when it was getting shortened out and thats why i get the random miss. I am curious if the person who had his 4th cylinder cutting out if he has fixed it yet??

Random misfire with a 6 bolt in a 2g is normal...I get it like once every other day. Only dsmlink or a potmod will get rid of it. I also drove my car at least 100 miles before i got the first random misfire code so it is really random.
I also used to throw the code on the 7 bolt but that was really rare and i changed all my plugs and wires and it went away.

 

[Highwayrun]

I can say that the problem my car has is exactly mentioned here. Sometimes injector driver 4 cuts out while driving causing the car to shoot the code P0300 and start to shake. I am curious if the person who had his 4th cylinder cutting out if he has fixed it yet??

I was going to provide a general update, then I saw this post and thought it better to reply here instead.

Since I used fuel injector cleaner a while ago, I have not had any recurrences of P0304 at all. That's about two months by now.

FYI: my method was to run the gas tank almost empty, add the full bottle of injector cleaner and then drive the car at high rpm and load until it was time to hit the gas station.

Getting back to the original poster's problem of P0300, may I suggest replacing the fuel filter in the engine bay, since P0300 indicates a multiple misfire?

 

[PieEyedPiper]

I was going to provide a general update, then I saw this post and thought it better to reply here instead.

Since I used fuel injector cleaner a while ago, I have not had any recurrences of P0304 at all. That's about two months by now.

FYI: my method was to run the gas tank almost empty, add the full bottle of injector cleaner and then drive the car at high rpm and load until it was time to hit the gas station.

Getting back to the original poster's problem of P0300, may I suggest replacing the fuel filter in the engine bay, since P0300 indicates a multiple misfire?

The fuel filter was replaced maybe 5000 miles ago? I'm positive it's still good.
I'm fairly positive it's my CAS.
I'm just waiting until i cant take it anymore and give kragen 79 bucks for a new one.

 

[verytalonted]

Any updates?

 

[EnticivEclipse]

any updates?

 

[ryno]

I had the exact problem and yes it was my CAS!

 

[PieEyedPiper]

I had the exact problem and yes it was my CAS!

Thanks for contributing, I'm glad you got your problem all sorted out

 

[PieEyedPiper]

Heh, well I've been dealing with this for the better part of a year now and i've still not managed to fix it.

Has anyone ever taken their CAS apart before? I dismantled mine yesterday and found it to be full of oil (darker than the rest of the oil too). Is that normal?
I cleaned it out and re-installed the parts hoping I would have fixed my issues, but my daily commute to school shot me down...again

I also have some more information. Many people with the 7bolt Random Misfire experience this on the HWY at 3000-3400 RPM. It just so happens that I have an exhaust leak (that I can't find, ironically enough) that will make the car run rough/loud during that rpm band.
Think it could be related? Seems like just a coincidence cause itd be really strange for everyone else that has this issue to have the same exhaust leak.

So yeah to sum it up I'm getting REALLY sick and tired of this crap. I'll be searching the classifieds for a new CAS this week. I'll let you know if it was the culprit (yes I know I should have swapped in a new one by now ).