PO300 Random Missfire Code 2G

[KrazyRob]

99 GSX. Im getting a PO300 code every so often.. with in like every 70 miles or so.. i have 97 gst that runs fine.. so i did a few quick swaps on parts one at a time to see if the intermittant code would pop up.. so far i swapped out the coil.. that didnt work so i swapped out the ignition module and that didnt work... i have not changed the plugs or wires yet as they are in good/ new condition but i guess that is next.. but would plugs and wires cause a " multiple" random missfire on ALL cylinders for a few seconds, throw a code, spudder, and then run perfect leaving the CEL on and code stored? Wondering if my ECU has a random problem going on.. how would i fix that? Sucks cause im kinda tapped out $$ right now...and re flashing ecu would suck.. Also would a straight 3" open exhaust cause this? There is no Cat or restriction... thanks..

 

[PieEyedPiper]

You and I may become good friends. This is one of the primary reasons I stay on the board.
Firstly, have you searched for other threads regarding this issue? The next question I have is how old is that clutch installation and which flywheel is being used? Could you imagine that the clutch installation could be the cause of the P0300? Does the P0300 happen at 3k, or just a hair below/above? Do you get a CEL during accompanying this behavior? Can you eliminate the behavior if you throw it in the neutral and allow the revs to idle and then throw it back in gear and all is well?

 

[96' Eclipse GS]

"Camshaft position sensor".......

http://www.dsmtuners.com/forums/newbie-forum/260269-multiple-cylinder-misfire-p0300.html

Post #15.....

http://www.dsmtuners.com/forums/newbie-forum/242628-problem-while-freeway-crusing.html

 

[KrazyRob]

My clutch sucks for a daily driver! it is for racing application only and stiff is all hell.. It is a good clutch for racing but on the street its annoying.. The kid who owned this car before paid to have this 6 point ACT racing clutch and flywheel installed.. it has like 10k on this clutch.. wonder if this clutch set up could be giving me that code...

Yeah it seems to happen on the freeway maybe after boosting and then getting off the gas and letting the RPMs fall.. It seems like when the RPM is falling while in gear the spuddering starts and the CEL comes on.. then if u give it gas its like its running on 3 cyls and spudders for a while almost have to get in the slow lane.. the last time it happened i pushed in the clutch on the freeway so that the rpms would fall and then the car died out and i had to pop the clutch while coasting and it fired up and ran fine but the CEL stayed on with a PO300 code and a pending PO300 code.... this sucks.... sometimes its hard to notice exactly what rpms it happens at and what gear because it is something that takes a while to duplicate almost 60-80 miles. And when it happens it happens fast, so sometimes you forget to check what you just did to cause this.. cause u could be on the phone, or talking to a passenger, adjusting the radio ect.. it sucks!!

 

[PieEyedPiper]

It's pretty much rpm and load dependent and will happen around 3k. Basically 70mph or so.
The next time it happens, take the car out of gear and don't let it die this time, get it back in fifth and you'll notice you still have the CEL but the driveability is back. And you're right on about the intervals between occurrences. Sometimes I was only able to get 4 or 5 miles, maybe less before the P0300 would hit again.

The only thing you can do in the mean time is cruise below 3000rpm and get good at managing the problem when it does happen. I got so good at it it was like second nature.

Unfortunately, I would not recommend anything to you specific situation other than a new clutch/flywheel install.

 

[KrazyRob]

Yeah I wish i could be 100% sure that the clutch/flywheel is the PO300 culprit.. Its not a cheap fix to try.. and a pain.. Dont really need to keep it under 3000rpm.. I can run it up to 7k no problem off and on up to 60-70 miles before the CEL comes on and the spuddering happens.. And the length of the spuddering motor varies, sometimes it only lasts like 5-10 seconds other time 30seconds to a minute... Very frustrating

 

[PieEyedPiper]

When the sputtering happens never let it go for that long. I've never tested how long it goes because, well I think that's ludicrous. When it happens, put it in neutral immediately.

Your case may well be different, but I think that you will find that you do, indeed, have access to all 7000rpm - it's just the the P0300 is much much more likely to happen around 2950/3150rpm when cruising/light load. Trying to commute at 3k was a nightmare.

As far as cost, I hear ya. I rode around with this for years before I swapped my clutch and flywheel out. Never seen it since, about 3 years later.

 

[H@xtGSX]

Add a 1g CAS to that mix and you have my car. I have a ceramic 6 puck with a Fidenza 11 lb flywheel and had to pot mod the car. It wouldn't pass 3150 under cruise without throwing a P0300 code. Ever. The pot mod had to be adjusted pretty high to stop it also, and that goofed up the timing. This coupled with the SAFC I was using, and I wound up having to drop the base timing to 1 degree BTDC, just to keep the knock to a manageable level. I wound up getting a 98 ECU, a Tactrix 2.0, EcuFlash, and CeddyMods and just reflashing the ECU with the P0300 code turned off.

 

[PieEyedPiper]

Would you recommend the pot mod at all?

I don't, simply because I haven't tried it. At the time I was still quite green and was "too scared" that interrupting the baro signal or whatever would hurt the car. If the OP seeks driveability this might be the ticket.

 

[Artago]

You and I may become good friends.

... me too except mine went away after many changes. I have no idea what I did right to solve it.

 

[tonyseagle]

This happens to me also. Same RPMs, but more or less 55...65...75 mph. Usually on a slight decel. All I do to get rid of it is quickly turn off/on my car and it goes away.

 

[H@xtGSX]

I would NOT RECOMMEND the pot mod. Taking away the barometric compensation really messes with your tune. Everytime the weather or temperature changes, you have to adjust the settings to compensate. It works, but it is a pain in the ass.

 

[KrazyRob]

Sounds like ALOT of people have had this spuddering po300 code. Guess im just gonna have to deal with it till i can save up to change back to a less extreme clutch and flywheel... I noticed that my clutch pedal has been reinforced and has a support bracket welded on so it wont snap in half from pushing in this tractor grade clutch.. I think my left calf is getting larger than my right from this chattering clutch work out haha....

Speaking of timing i think my timing is retarded to much after i did a timing belt job. I dont have much take off power and it takes along time to spool with this hmi e316g. According to the timing light it looks like the mark is sitting near the middle btdc mark which i believe reads 15 btdc. If that is a 15 btdc mark on the cover then at idle its runs about 800 rpm and the mark moves around alittle from 15btdc to 9 btdc...

I think before i did this timing belt my timing was advance like 5 degrees or so and my car was quick as hell, but then again i had a 50 trim turbo, large 680cc injectors, GM MAF and MAF Translator that i had to take off for CA smog...im running all stock now with the exception of the e316g and 3" exhaust.....what is a good timing mark to set my car at? And how do i advance it without taking the car apart? Rotate cams?