misfire
03-14-2010, 11:53 AM
#1
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Location: Sacramento, CA
Posts: 179
Car Info: 02 wrx wagon
misfire
i have an 02 wrx with an AP stage 2 tune with a catless down pipe. ive had no problems then back in december it started to randomly miss it doesnt matter what RPM im at or how much throttle i give it, it doesnt matter if its hot or cold, or right when i start it up or after 45 minutes of driving it just randomly misses sumtimes alot to where it barly runs or just misses once n doesnt happen again for a few days. it hasnt set a miss code only a cat ineffecency code. and a fuel level sensor code. is it really the front cat(since i have a catless DP) or possibly the 02 sensor? or mabe even fuel related since it hasnt set a miss code?
any suggestions are appreciated. Thank you
any suggestions are appreciated. Thank you
03-14-2010, 08:13 PM
#2
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Location: Ventura, CA
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Car Info: 04 EJ207 6mt WRX, 08 Spec B
How many miles are on your wrx? Ever change plugs, or basic tune up? Out of curiosity what is the value reading on the DAM on your AP when this problem is occuring try to post up some data logs itll be easier to help you with these.
03-21-2010, 01:35 PM
#5
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Car Info: 02 wrx wagon
I have 138000 miles. Ive narrowed it down to a fuel pressure problem either with the pump or the regulator. I put a fuel guage on the car an when it feels like its missing the fuel pressure actualy drops below 15psi as opposed to the 35-45 its supposed to be at. I need to do more diagnostic work and will post my results later
03-22-2010, 06:47 PM
#7
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Join Date: Mar 2010
Location: Washington
Posts: 9
Car Info: 2003 wrx
Same thing for me. Mine is catless also. It's weird though becase when itdoes the car runs bad. Like when I acclarate the turbo usually kicks in about 3k rpm but lately I get turbo lag and once the " fart" happens the car just lifts up
03-23-2010, 08:32 AM
#9
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Car Info: LUMPY CGM 05 WRX
Im going to state the obvious but i would change the fuel pump and reg before running it anymore. It may not be missing it may be detonating. They are both relatively inexpensive.
03-27-2010, 11:18 PM
#10
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Location: Sacramento, CA
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Car Info: 02 wrx wagon
Just changed the fuel pump nothing changed, its still messed up. And i dont know about the valve lash how would that explain the fuel pressure dropping very low? Im going to go through all the wireing now to see if i find anything unusual there.
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