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High RPM Misfire! Please Help!

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24K views 33 replies 7 participants last post by  ssnataku  
#1 ·
I have a 2002 wrx with up-pipe, tbe, and a k&n typhoon, I was recently running the xpt stage 2 map but was having the misfire problems, I figured that I may have screwed something up with the reflash but decided to make the jump to the cobb ap. The problem is the same, whenever the car has been running for a while and I put a load on the engine while in 4th or 5th gear my car misfires. Can somebody tell me what my problem may be, when the engine is cold it runs great?:confused:
 
#3 ·
you have a wideband? What's it displaying? Log the car.
 
#6 ·
No.

You could start with logging without the wideband. What boost are you hitting?

Check for any leaks associated with your intake & clean the MAF. Check for excessive oil in the intercooler. Check the plugs.
 
#8 ·
well i cleaned my MAF, it was a little dirty and the connection was dirty as well, I also pulled intercooler off and noticed that there was a very small amount of oil on the inner lip of it, Maybe enough to equal a small drop, I also checked my lines and hoses goion to the turbo and the larger hose that connects to the turbo was lose, not the line that goes from turbo to intercooler, it was the large one from the air cleaner. any ideas?
 
#10 ·
The amount of oil from the intercooler is normal.

The loose hose from the air cleaner was quite possibly the culprit. If your turbo was sucking in outside air there it would cause a lean condition. See if it helped.
 
#12 · (Edited)
Okay.This has been suggested like 3 times.LOG THE CAR.Send the logs to XPT................. on that note it could be a fuel pump going bad or a clogged basket.You need to have the fuel pressure checked.It's a PITA because the WRX's don't have a test port/schrader valve
 
#15 ·
does it do it in lower gears?

If not, your clutch is slipping, that would explain the jerking feeling but not throwing misfire codes.
 
#17 ·
as testes said, clutch possible. 3-5th gear puts much more torque-load on the clutch. A clutch will have more tendancy to slip in higher gears, 3-5 (6).

You really need to log the thing, for us to have a better idea and easier to possibly pinpoint the issue.
 
#19 ·
#25 · (Edited)
#26 ·
yeah and when I go to finish the install I get that stupid error, This morning when I was comming to work I tried to load it up again while watching the air fuel gauge on the ap and when It shuttered it dropped to 11 on the a/f and then lost connection to my car, twice, then flashed a misfire on cylinders 3 and 4
 
#27 ·
sounds like it's getting extremely fat, and fuel-fouling the plugs ??
 
#29 ·
check one of the misfiring plugs, to see what it looks like. post a good picture of it, if you need help.