Why does my car backfire?

[blackfire93]

Whenever I start my car cold and rev it up to about 3000 RPMs it will backfire. I just put my SLP loudmouth on about a week ago. The loudmouth isn't the cause of it because it did it with the stock exhaust too but it's just more noticable without a muffler. Any ideas of what's wrong. I'm leaning towards the idea that my opti-spark might be starting to go bad after 94,000 miles.

[DJ Taso]

I've got the same problem, but my car bogs more than it backfires.

[4THGEN Z]

is it backfiring or a popping sound when you let off the gas?? If its popping when you let off, then its normal IMO. Mine does it too when cold.

[blackfire93]

It's a couple small popping sounds and then a really loud pop. I'm not sure what's the difference between that really loud pop and a backfire?

[94 formula]

Is it only for the first few minutes? Does it do it after its warmed up? If its only at first its because your in either closed or open loop I forget which is which. That is when the car is not using the O2's and is just using a default setting. Whenever your warmed up and get into either open or closed loop (the opposite of what it is warming up) it should stop. My brothers 99 Z28 with 30k miles on it even does that.

[fastTa]

With stock manifolds, and the design of the y-pipe type system on our f-bodies, it is common for the exhaust to pop like you described.

[MN6WS6]

I have the same issue. I have two bullet mufflers on what is otherwise a straight exhaust, and I hear it too, mostly in open loop. You don't hear it as much through stock exhaust, but when that muffler is gone, it really shows up. Completely normal.

[blackfire93]

thanx for all your knowledge

[02Z28]

ah, the joys of having a remote start option on your car alarm! start it up about 5 mins before you go anywhere, and viola! no more popping!

i've noticed that on my car too when i forget the remote start and it first starts up....usually notice it when i'm shifting