Solved: see post #5

about 500 miles ago i installed a new clutch and flywheel. needless to say its been almost 500 miles of no boost and no shifts over 4k.

a handful of times in that period ive experienced a missfire on the highway at cruising. i can feel the missfire so i know its not a phantom code. when it starts i can push the gas a bit further down and it gets worse (typical for a miss, increasing load). but if i let of the gas and get back in it, it goes away.

im running stock maps, stock wastegate, 80mm TBE, perrin intake. i can pull the codes, and everytime its a p0300, multimiss. im not finding a specific cyl missing. i recnetly installed a wideband and noted that it goes full lean when this issue arises. the plugs also indicate a lean condition.

anyone have this issue, possibly a fuel pump intermittantly spazing out?

thx, Cory

 

nobody?

I put a set of plugs in just to see if it was simple as poor spark, but this afternoon it did it twice in a 5min period on the interstate. ill try to post up a datalog of the issue occuring soon. i didnt see any red flags, but some of you guys might.

plus, is it normal for a wideband to read full lean when fully off the gas and in gear? poor airflow over the sensor?

 

Try to change the coils. Should help it out. Whenever you have a misfire, it usually will not have to do with fuel if its while normal driving conditions. Replace the coils and you should be fine.

 

Finally got a good log of it

 

Found this.... shall try soon!

https://www.evolutionm.net/forums/ec...ml#post5924991

 

switched and still running 0015... yesterday switched to tephrav7 94170715.

running since feb 23 with no issues
Problem SOLVED!

 

my car likes to fire once in a while when i -put my foot down in fourth..sometime spits a flame as well

 

sounds like it dumping alot of fuel, might check your acel enrichment.

 

Wow, I have been having this same issue. Too bad my dealer is 2+hrs away. I can't make it 10 miles without it throwing a code

 

which issue? post in your regional forum and see if someone can flash your rom local.

 

I have been having the P0300 code as well. I just went to the dealer in Glendale, CA (best dealership I've ever been too...thanks to Paul) and they reflashed my ECU. It definitely made the car MUCH smoother to drive but the code still pops up - though it takes longer now. I am thinking that my head might have damage and the valves might be bent by the previous owner. The coils, wires, plugs, cams, sprockets, etc have all been replaced. I am going to take the head off and upgrade the valves (with OEM springs and probably OEM retainers).

 

if it were a valve seating issue, it would miss all the time. did they tell you which rom they flashed to the ecu?

 

They told me that they can only download the latest one. I tried to verify which one it was specifically but not one took notice of it when they did it so they couldn't be sure.

I have a slightly rough idle as well. I wish there was someone with a factory Evo that I knew so I can sit in a 8 and see how it should feel. There is also a bit of valve noise but that wouldn't cause the misfires either. I have my plugs gapped to .024" and have used both iridiums and copper. I'm really not sure what it could be at this point but I really can't go more than 30 minute on the highway without it giving me the code.