So I'm having a misfiring problem at low RPMs(1k-2.5k).
2001 Z24 - 2.4 LD9 MT
96k Miles
CEL- P0420 Catalyst Efficiency
I've replaced the following in an attempt to fix problem:
-Catalytic Converter
-IAT Sensor
-O2 Sensor front (rear has simulator installed)
-Coil Packs (both)
-Coil Pack Housing
-Spark Plugs (tried both AC Del Plats and NGK Ir @ .040, .050 and .060)
-Plug boots
-Fuel Filter
-Checked for exhaust leaks
-Checked for vacuum leaks with carb cleaner
I just put in new NGK Ir plugs because I thought maybe I got a bad plug out of the box.
Here is a pic of the AC Delco Plats I installed only 3 weeks ago...
Same problems with new plugs although it does seem to run a little better.
I've been reading every post I can find even somewhat related to my problem, with no luck. Using both the search on the .org and google
Any ideas or suggestions would be appreciated.
Quote:
-O2 Sensor front (rear has simulator installed)
Given the code, I'd say that your O2 simulator is not working.
I had one of those back in the day, and it did blow up.
i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick
Your cel is from your O2 simulator not working.
Your misfiring is because you have a blown head gasket and are getting coolant into the combustion chambers. You know how I know? your spark plugs look rusty if thats just the camera then I'm wrong. Do a compression test.
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ya with a simulator how would you actually know if all you fixed was wrong in the first place.... the ecm dont know if the cat is good or not if its getting a simulated signal..... you couldve been chasing air with that code...
ʇı ɹǝʍo7 | ǝcoMonstǝrs
I am not necessarily chasing the CEL... most of the parts were in attempt to fix the misfire. I only posted the CEL because I figured it should be noted, even if it not %100 related. I am just concerned about the misfire. As far as it being a head gasket, wouldn't it let coolant in at higher RPMs too? The misfire I have only happens at very low RPMs and not very often. After 2k RMP's its unnoticeable, in fact the car runs great. Going to do a compression test in the morning and post results.
I hope it's something cheaper.... or at least something I can upgrade while am at it. They don't make "performance" gaskets do they?... ebay here is come! lol jk.
Actually you'd have less vacuum at higher rpms and it MIGHT not suck coolant into the cylinders at higher rpms. Just do a compression test, borrow the tester from autozone and its a free test.
1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by:
Kronos Performance
WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
