yup. i was drivin back from sacramento and i counted it atleast 30 times. (thats with the cel light on).. it got quite annoying too (laptop died).

 

You might be a perfect canidate since you have issues with this.

 

good . i'd love to be the guinea pig

 

after doing my clutch withLightened flywheel PO300 has been the story of my car.Makes me thing I have meth delivery problems timing fuel or other and in the end all I have done is change the fly wheel?

 

shaggy. its the lightend flywheel that is causing the problem. if ur car makes a popping noise when ur on the meth then thats yoru plugs. re gap them to a smaller gap or get a new set of plugs if that doesnt work.

 

I don't have this issue anymore, however it's a very common issue that affects alot of VIII's and plays havok on these guys getting an inspection sticker. If you fixed this you could easily sell the patch for a nominal fee and I think you would do alright. Or even the current donation, most of the people who have this problem have spend plenty trying to solve it with very little success.

Hopefully someone who is afflicted with this can chime in with map revisions that are affected but I believe it affects all of the USDM VIII roms.

The current belief is that transmission harmonics cause the ECU to believe the engine is mis-firing (its not) and then it flags a P0300, and then something in the logic is flawed as the code actually causes the car to start mis-firing, Resetting the code fixes the misfire condition. It's a relatively well documented problem and their only solution has been putting a c-reader on the obdII port to clear the code as soon as it occurs. Transmissions have been replaced to fix this as well, I dont think it only affects cars with lightweight flywheels but I could see how that could exagerate the issue. Some of these cars have serious difficulty passing inspection and nothing is really wrong with them other than some harmonic vibration that causes the p0300 to occur. Does the ECU use the knock sensor to detect mis-fire?

If you search p0300 you may find some of my posts. My car had a different p0300 that was corrected through parts replacement / tuning.

 

i believe it might have to do with the lightend flywheels not being balanced and / or the lightend flywheel period.

 

I believe the P0300 has no relation to the knock sensor, but rather just front O2 sensor.

 

MY car dont miss a beat and i keep getting a missfire code. a fix/over ride would be awesome

 

you have 5s in the low load low rpm area?
sure you don,t have a intercooler pipe rattle or something like that?
even an exhaust rattle might trigger it

 

I believe this issue is something entirely different. Search and read some p0300 threads lots of cars on stock clutch / flywheel. Start reading the older posts first when the VIII's were newer. Maybe it's just a bad piece of code in the stock ECU. Mistakes have been found before. Either way, maybe the p0300 code could be turned off enginuity style if all else failed. Would something like that make it fail OBD2 diagnostics for emissions testing? These cars seem to be overly P0300 sensitive. I saw that Tephra is going to check into it when he has time. That's good news for those that have this problem.

My car had 5K miles when it first got a P0300, 12K by the time it was repaired. It had the issue for 9 mos and made 5 visits to Mitsubishi under warranty. My car seemingly ran fine the whole time but a brand new car with a CEL is not acceptable. I guess the good thing is this is actually what got me interested in tuning EFI. My car evidently ended up being a fuel trim out of bounds that was caused by a cruise load/rpm intermittant injector malfunctioning. Or at least that's what Mitsubishi would have me believe, maybe makes sense now. Was a brain twister when it was going on.

This is a list of what I did or replaced to try to fix the issue myself.

called Dynoflash repeatedly for support, not much help but he did reflash me to stock (mail in, about a week) but he took 6 weeks to email my tune back to me. returned car to oem (removed cb, mbc, drop-in), stock clutch/flywheel
oem version 13 rom
bought tactrix cable and started logging car, some trim fluctuation but I didnt really know what I was looking at then
bought wideband idle afr 14.7 at idle, rich under boost on OEM tune and dynoflash tune 9's and 10's respectively
flashed oem version 15 rom
checked for boost leaks
checked for exhaust leaks
plugs
wires
coils
compression test

5 trips to the dealership

1st trip to dealer they just reset the code, code came back a week later.

2nd time to dealer they reset code, blamed bad gas (I use Shell 93 from one station WTF?)

3rd Performed upper engine cleaning, charged me $150.00. Compression tested car, cleaned plugs which he says were fouled (WOT is plug cleaning according to tech). Plugs had just been replaced at 5K miles, this was maybe 7500 miles. Told me I probably dont get on it enough.

4th They called mitsu corp engineer and had car for a week. When I called they said they were replacing the injectors and that's why it was taking so long. I found out later the engineer advised injector replacement but the local tech didnt agree (he had never seen a failed injector in his life????), He cleaned them again. On the way home I got the P0301 again.

5th time, I brought lemon law paperwork with me for them to fill out when I dropped the car off. Service mgr says "Were gonna replace the injectors". I said, "You told me you were doing that last time I talked to you, fill out your portion of the paperwork please (service history), this is your last chance to fix the car, good luck". They replaced the injectors and I havent had P0300 since. I made sure the check engine light still worked after the code didnt come back.

 

Glad to hear you got yours fixed, sorry it took the stealership so long to get it right. Those of us with many after market mods seem to be at the will of our tune! LOL Since mine doesn't affect my performance I just live with it!

Josh

 

hmm.. well whatever it is guys its really freakin annoying. i dont even drive the evo that much now since i bought a new honda (91 hatch baby!) cause of the p0300 (very very very very annoying) and mainly gas.. its a money pit :P.

- shane

 

I have an 03 with the ACT Prolight flywheel and the knock tables are untouched. I have 33000 miles on my car and have never had the P0300 code. There was a thread a while back about Shep traced it to the 4-5 synchro. I bought my car used and the synchro TSB was done. 22000 miles on it since I bought it and not a problem with the P0300.

 

I thought the majority of 0300 random missfire had something to do with idle/off idle transition and timing which was fixed by advancing a little in that area. Anyone?