Backfire Problem?

[WS600]

Someone please help. I recently changed the heads (stage 2 64cc), cam 222/224, crank pulley, altenator pulley, LT headers, LS6 intake manifold, Screenless MAF, timing chain, oil pump, smooth belows, lid, large diameter y-pipe, loudmouth exhaust, 36lb. injectors, and 3.73 gears, on my 2000 WS6 Trans Am automatic. I paid to have it tuned by LG motorsports and it dosent seem to run right. Recently i started having backfiring problems, bad. It backfires at 60% throttle or more and generrally only at 60+mph. Added to this problem I started hearing pinging to (I do use high octane gas). I purchased EFILive in an attempt to fix the issue. and have made a few adjustments (mostly to transmission settings). Please someone help, I'm not sure what the problem is and how to fix it.:

Also it only backfires when I'm actually in gear, if i run it up to 5000-6000 rpm in neutral it's just fine. (not sure it matters but i thought ,i'd throw it out there)


If someone can take a look at my tune and log and perhaps give me a little advice on what to do. Yes, I'm a newbie, but i'm dedicated to getting this right.

[Bruce Melton]

Try the crank sensor relearn.

[WS600]

I'm gonna give it a shot right now. Thanks... Yeah just tried it and didn't change anything. I don't know what to do.

[jfpilla]

Suggest you not go hard on the throttle until you get the tune squared away. It really is bad across the board. I can't believe a pro did it. There are knowledgeable people that can help you on this Forum and can at least point you to some tutorials. You can also get mail order tunes here that would be a good start.

[WS600]

Yeah, your probably right, I don't want to break something. You should have seen where he had the shift points it acted like there was no 3rd gear and stayed in firts intil 32mph no matter what the throttle position. Is the entire tune bad or just air/fuel or any suggestions.

[jfpilla]

It's pretty bad. I'm on ther way out right now. Hope someone can get you started, but it is saturday night.

[WS600]

I hear ya, think i'm calling it quits tonight. It's beer time, take it easy.

[WS600]

I read that someone else had the same problem and he fixed it by just changing the plugs and wires. Mine plugs/wires only have about 1000 miles on them. Could they have gone bad?

[jfpilla]

I read that someone else had the same problem and he fixed it by just changing the plugs and wires. Mine plugs/wires only have about 1000 miles on them. Could they have gone bad?

You can't rule out mechanical issues, but the tune is .

[Bruce Melton]

Are you saying that the tune as posted above is what was derived by LG for your current configuration?
If so, they owe you a redo or is there is something you are not telling us?