I think you might be onto something here. I live in Colorado and I just got my first P 0300 right after i put on my ski rack. I also suspect bad gas and cold snow temperature plus my XEDE and my new transmission to have something to do with it. Too many compononents.

 

i juss got evo back from my dealer...it was there for 3 days..
and i asked them how did u guys fixed the 0300 problem, and the technitian said "we just reset the ecu",i was like isnt there a reflash for that code from mitsu headq? and he said "we dont have any reflash from mitsu corp....", FAWK it took them 3 days to just reset the ecu...damn...i hate em...

 

This is exactly why I don't want to waste my time taking it into the dealer. I am just trying to avoid cruising between 75-85. Either 75 or 90+mph.

 

Heh, Mitsu just voided your warranty due to your ski rack!

 

You guys that are having this problem repeatedly, there is no fix, so your only option is to live with it or lemon it. Simple as that.

 

I disagree. Short answer, new non-defective tranny and/or new standalone ECU. Long answer, read on:

I threw the P0300 code 2 months after buying my car with absolutely no mods and a babying driving style, took it in to the dealer and they regapped my plugs, cleared the code and scratched their heads. This was pre-reflash recall. I have heard of so many people that took their Evos in for the P0300 reflash seeing no change in occurrence of this code post-reflash that I hesitated to take mine in, also didn't want to return car to stock just for a questionably valuable service.

Ask Secret Chimp and others. The consensus is that the problem that causes this is driveline noise caused by defective transmissions on some, not all Evos. This noise literally shakes the engine of the car through the driveline resulting in two possible scenarios:
Now, I have an Exedy twin being installed as I type at Altered Atmosphere here in Maryland. [Side note: they added 2 hours on to their estimate and are charging me for it so I am plenty upset, though they have promised to make this up to me in parts discounts in the future.] This Exedy could make the problem worse if driveline noise is the culprit, but since my clutch is dead anyway, I'm hoping this will help. If there was slippage causing this problem, perhaps this will correct it.

If you believe the "driveline noise" theory #1 only, you can go buy an AEM (or other) standalone ECU, stick it in and never see a P0300 error code again as long as you tune the AEM properly.

If you believe the "driveline noise" theory #2 (or #1), as I do, there is a fix: a completely new and rebuilt transmission that doesn't shake the driveline improperly. Lancershop has new 5-speed trannies for about $3000 right now, so that's obviously an insane amount to spend on what amounts to a defective car situation. My plan is this:

Drive my otherwise wonderful Evo until the engine explodes from possible misfire and I buy a used Honda beater, or perhaps wait until someone sells the Evo MR 6-speed tranny and can do a conversion, at which poin't i'll stick it in my 2003 Evo and never look back.

Please, anyone, offer technically sound arguments against what I have written here because I would love to believe that I am wrong and a simple reflash or some such tweak would cure the neverending P0300 misfire code on my car.

Thanks to all who are working for the benefit of all of us to solve this and many other Evo problems through evom.net.

Best,
Adam

 

I should have clarified, there is no warrantee fix nor is there an official Mitsu fix that works. They are very unwilling to replace transmissions and the problem will occur again if you do (this thread holds all the evidence of that). You have to be a lucky SOB with a great district manager to get any sort of approval for a transmission replacement. Since you have no warranty remaining anyhow (thanks to mods) this is all a moot point to you, hence your post.

A standalone will cure it but you are SOL with Mitsu if you go that route. Not that it really matters I suppose, but I don't/didn't/won't want to spend $1500 on a fix for a problem they should be paying for.

I am awaiting the first MR p0300 issue, but I doubt it will happen. I can only hope they managed to work around this issue with that transmission.

There is no technical rebuttal to your post, you are right but somewhat wrong. My belief is #1, but that the problem lies within a clearance issue not with the drivetrain noise we've all come to love and accept. There is documentation of this issue on the forums here as well.

 

BTW I wasn't calling RedUSEvo a sob.

 

First time I got the P0300 code the dealer replaced 2 fouled spark plugs, they cleared the code and sent me on my way. Second time i threw the code kept the car overnight and reflashed the ECU, that was just 4 days ago.

Last night I was on my way home about 270 miles into a 340 mile trip the SES light comes on again. I stopped into Autozone today confirmed 2 0P300 codes stored!

Thats the 3rd time in less then 30 days I threw a 0P300 code, for a 100% stock car thats less then 2 months old with just about 7,100 miles thats not right! I didn't spend 30k to look at a SES light. And to make matters even worse I still have to get the car inspected (purchased out of state) but with the light it won't pass safety inspection.

I thought the exact same thing, all my SES lights came on in 5th under light or no throttle. I think its the driveline vibrating too much that the knock sensors detect "false knock". I'm going to take it back to the dealer next week and see what they say. I don't want to give up on my EVO but I think it maybe time to start researching the lemon laws.

 

Which plugs are folks installing with some degree of sucess? Thanks!

 

Another lemon! Do it up!!

 

None. I went with the Denso IW24s and still had the problem.

This is not a spark plug issue. There are 2 main causes of this problem, only one is a real actual misfire. 1) stuck injectors (real misfire), 2) false knocking (under speculation as to what causes this, Mitsu has said nothing official).

 

I second this! Those of you that choose to live with it will have trouble with smog in the future.

 

well I made another appointment for this afternoon, I honestly think the dealer has no clue what is causing it. They have been excellent in dealing with the problem by letting me use one of there fleet vehicles everytime I drop my car off.

I hope they can fix it cause I love my EVO and don't want to give it up.

The funny thing is that I got the 2nd 0P300 code about 270 miles into a trip so I went to autozone and cleared it, well heading back up the same roads 270 into my trip the light came on again, very strange!

 

It's not strange at all. Welcome to the p0300 woe world. Your dealership will be useless in fixing this (except for racking up service visits so you can utilize the lemon law).

http://www.lemonlawamerica.com/