Ok. I have Pettit ECU,cheap airbox mod, Downpipe, hi-flow cat, and catback.

Now the problem. When car is at idle it appears to be fine. Bring the rpms up around 2.5k and keep them there and it seems to miss and backfire a little(like alot of tiny backfires). This all goes away of coarse when I accelerate. It seems to only do it when I am sitting at 2.5rpms(for emissions)

Under WOT its working great. I've changed the plugs and it still does it. I've also noticed that the car is backfireing a good bit more than it did last year with the same mods.

Any ideas?

Thanks

 

bump I'm having the same issue.....anyone have ideas? I have a Power FC so I can tune this out if someone can help. This is the only area of the smog test I fail