: Still popping and farting...HELP



fazz1225
06-21-10, 09:52 PM
Ok the car starts and runs fine, it gets to about 180 degrees and will run great . No problem until you turn it off.... Once I turn it off than try to restart it while its hot it pops and farts ( backfire). I checked codes and called for misfire and o2 sensors. I put Kooks on and high flow cats, new o2 sensors and it still has the same scenerio. WTF, Any help would be great, by the way no codes since the reset and new parts. Another note after the loud backfiring the passenger side cat was red inside. Thank you in Advance:banghead:

kevm14
06-21-10, 10:28 PM
Without having specific knowledge on the Gen III and up engines, that sounds a lot like a solid state ignition type module going south. Late/wrong/no ignition would cause those symptoms.

And I just remembered there are 8 coils so....doesn't the PCM talk directly to the coils?

Baltimore07V
06-22-10, 07:59 AM
Ok the car starts and runs fine, it gets to about 180 degrees and will run great . No problem until you turn it off.... Once I turn it off than try to restart it while its hot it pops and farts ( backfire). I checked codes and called for misfire and o2 sensors. I put Kooks on and high flow cats, new o2 sensors and it still has the same scenerio. WTF, Any help would be great, by the way no codes since the reset and new parts. Another note after the loud backfiring the passenger side cat was red inside. Thank you in Advance:banghead:

Well your running rich, so it could be the PCM, the coils, or the plugs. I would start with the plugs, as they are the cheapest to replace. You could also get the car tuned as well, especially after hi-flow cats + headers.

A dying altnerator or bad ground has been shown to cause similar isssues too boot.

Start with the simplest and cheapest solutions. First step would be to clean every ground in the car with a wire brush, and make sure it has good contact with the frame of the car. Second would be to replace the spark plugs. Based on any changes, work backwards from there, to see what the issue is.

fazz1225
06-24-10, 10:52 PM
changed coils and still same, i was told maybe a lazy valve (bad valve spring) any advice on that?

darkman
06-24-10, 11:07 PM
A compression test will tell you if there is a valve related problem. Did you have a tune following the header install? Headers without a tune will usually result in a rich condition.