backfiring?? what would be the cause?

94convgt

Founding Member
Mar 1, 2001
140
0
0
las vegas
My car has been backfiring really bad lately. It only happens on decel while in gear. It doesn't do it all the time but when it does.....BOOM!!! Sounds like a shotgun right behind my head. Scares the **** out of people around me too. It's getting kinda embarrassing to say the least :( The worst part is i was cruising through traffic the other day with the top down and she let a big one out. I ducked for cover and looked around like what the hell was that. I then noticed everyone looking at me like a complete moron followed by disgust. :notnice:

Any help would be greatly appreciated.
 
Have you checked your timing lately?? It's GOTTA be off. Often those BOOMS are caused by gas remaining in the chamber and igniting during the exhaust stroke. Check the seals around the headers (if you got them) and the rest of the exhaust system too.
 
Check your exhaust system too. My stock h pipe got a little old it broke right above the first cat and I really couldn't see it until I took the pipe off. You can probably feel up around the cat. My car was backfiring real bad until I replaced it.
 
Thanks guys for the replies.....i'll check the exhaust to see if it's leaking. I have Mac shorties on it with a Prochamber and full exhaust. The EGR is disconnected so that should be fine. I'll double check the timing because the last week or so it's been acting up every now and then. It acts like 1 or more plugs are fouled out and starts missing pretty bad. I can't wait to get the AEM on it so i can see exactly what everything is doing. I know that won't cure everything but at least i can see inside things.
 
I found the culprit :bang: 2 of my header bolts on the passenger side were almost falling out. I couldn't see them because of the sparkplug boot cover. I tightened them up with some locktite and she ran like a raped ape. No backfires and idled fine. I can't believe i was soooo stupid and didn't notice it sooner being that it's happened a bunch of times.