LOL, I know I keep asking questions about this and that, and thanks everyone for the help.

Anyway, ever since I got my car back from the shop after a non-seq build, it is making slight backfiring noises. Not under deceleration, but when you slightly tap on the gas pedal on 3rd and 4th only (3000 to 4000 RPM). It does this only when I apply very little preassure on the gas pedal, if I go WOT it does not do it.

I can feel the explosions right under my seat, approx., more or less where the catalyzer would be. I am running a full 3" open exhaust.

I was told that maybe it was because the exhaust was not properly mated and some space was left en between DP and catback, air is being sucked in and since there is some raw fuel, it ignites automatically. It does not make much sense to me since I am slightly tapping the gas pedal.

I am also reading the AFR on the gauge, and when tapping the gas pedal, it reads in between 14:1 and 15:1, zero boost since only tapping it. So I dont think there is any raw fuel there.

Could it be the spark plugs? I remember vaguely that we went with two trailing on one rotor, maybe both. Why we did it I cant remember. If I am not mistaken, the only difference is temperature range, right? We went with the colder plug on I think both rotors.

ANyway, thanks.

 

sounds like a timing issue to me