Ok before I get into my issues with the car, I will post my mods.

CAR: 1997 Firebird Formula A4
MODS: 3.73 Richmond Gears, Jet-Hot long tube headers, custom true dual exhaust,Moroso CAI, weld-in sub frame connecters, SLP manual fan switch, 1LE intake elbow, Nitto 555R drag radials, Delteq Opti Direct Ignition, OBD-I conversion,madz28.com pcm tuning, other misc free mods, Lakewood LCA's, BMR Panhard Bar, Urethane trans mount.

Ok well, lately this idle issue is pissing me off. This what the car does. If I am at a stop light, waiting for it to change (car in drive, engine at idle) the car will randomly seem to have this very faint pop or backfire I can hear. It's your average backfire, because its just like a quiet pop. I doesn't seem missfire either. I get no codes. And this only happens at idle, while in drive, with my foot on the brake at a stop. Now if I throw it in netrual, it seems to go away.

This weekend I decided to keep an eye on the scanmaster while this was happening. While monitoring the Spark advance, I noticed while I am at idle, holding the break, in drive, waiting at a light, it normaly reads around 18-20. But when I hear that random pop, it normally jumps to 22-24, then goes back to the normal and 18-20, and it idles fine. I also notice the MAP # will jump up a point when this happens as well.

My question is this, would a bad IAC cause this? Or is this somthing else that is causing the problem. Can you guys point me in the right direction for solving this. It just started to pop out of no where. And I just find it odd that this is only happening at idle.

Thanks,
Mike

 

ttt

 

Hmm, the MAP # jumping up is probably what cuases the spark advance to jump up and probably thhe popping. why it is doing it IDK, maybe it is an electrical issue?

 

Yea its wierd. And it only happens at idle wtf!

Mike

 

Unplug the IAC and see if it gets worse or stays the same.

 

Unplug it while it is running, or unplug it before I start the car?

 

While it's running. If it stays the same then you know that's most likely your problem. If it gets worse it may or may not be the IAC.