I just recently sold my 98 Mustang GT and bought a 96 Cobra with 89,000 miles on it. I noticed that at a high RPM the car backfires really hard, sounds like a shotgun or something. It doesn't decrease the power by no means it still runs perfect but that backfire kills me. Anyone have any idea of what it could be or how to fix it. My A/F ratio gauge is reading a little rich 11.9.

 

If it was running lean I would say that was the cause but where it's just running a little rich I highly doubt that is the problem.

 

Yeah it definnetly not lean. It is running rich.

 

what exhaust is on it? does it "buck" or just pop really loudly?

 

When does it do it? Under throttle or when you let off? My car will pop through the exhaust when you rev it to the sky and then let off to grab another gear.

 

^ you have an h pipe don't you? possibly some SLPs?

 

No, its a pro chamber with some ghetto installed Mac mufflers... previous owner was too cheap to just buy a cat back so he had a muffler shop weld them in and they did a half *** job. Im planning on SLP LM1 after the engine build. Should sound wicked with the cams.

 

it might just be whats called lean pops man...all of our cars do it that have after market exhaust its just the unburnt fuel in exhaust combusting...if its one huge pop like uncle bucks car then ya you might have alittle prob