Backfiring
 

I have an 88GT (speed density) GT 40 upper lower (Lower is ported) I have been told that I may have to much intake for stock heads.

My question The car backfires between 2000 & 2500 rpm when you push the pedal down semi hard (ok at wide open throttle)

what could cause this?

I am thinking of going heads, cam, & mass air conversion in the near furture would this cure the backfiring?

Thanks in advance

Chuck88

My car had a backfiring problem for while. I found out I had a bad fuel injector. It wasn't flowing what it should and was essentially leaning out that cyclinder.
I replaced all 8 of them and haven't had a problem since.

When I had this problem a Ford dealer pulled the codes for me and did a flow test on the injectors. They just charged me for an hour of labor, which I didn't think was too bad at dealership.

Also, double check your timing. That can cause you to backfire.

check for vacuum leaks, timing, fuel pressure and also read your spark plugs

From what I understand a backfire is when you get combustion happening in the intake instead of the combustion chamber as intended. I thought there was only a few reasons for this to happen. First would be the timing of the valve positions and/or spark not matching the fuel injector firing. The other would be an extreme rich condition in the manifold such as when an injector is stuck open. Add a little spark and boom!!

Maybe a complete tune-up would help?

SilverSN95- That is a good point. My problem was a popping sound, probably not as loud as you would think a backfire would be, but still very audible. Sorry if this confused anyone.

sounds like timing to me, my car did the same thing and i advanced the timing a little more and it was fine
later
raini

Backfiring
 

You should check your spark plugs. My 94 cobra had a similier problem, it would backfire betweem 2500 and 3500 rpm's. it was a bad spark plug that was grounding out on the header!