Cyawn

I have a 93 trans am. I recently put headers, egr delete, set of wires, ngk tr5 plugs. After this my car immediately started backfiring and missing and it hardly ever does it at idle and I can even rev it up to 5K and it sounds good but when I put it under load not even WOT it misses and hesitates and backfires and even backfires on deceleration. I have replaced these to try to fix this problem the ignition coil, opti and a second set of wires and neither work but the opti did give it a good bit more power than before. I don't know what's wrong and I need help because after all that equals a lot of money and i don't want to keep putting money in it for it not to fix.

SS RRR

iTrader: (2)

I would start with making completely sure your wires are routed to the correct plugs. What you describe is textbook for a plug wire to be on the wrong plug. Also ensure none of the wires are burnt.

Cyawn

im positive the wires are on the right plugs I checked today for the 100th time.

SS RRR

iTrader: (2)

You changed out ignition components and it started acting up. All things point to something you did whether it's a burnt wire, cracked plug or wires routed wrong, backfiring is an ignition/timing issue.

Cyawn

I know my wires arnt burnt and are routed right. I've only pulled a few plugs and checked them and they were alright. I will pull all the others. I'm hoping I just got a hold of a bad batch or something.

SS RRR

iTrader: (2)

Is it backfiring though the exhaust or intake? Your EGR delete may be suspect too. Did you install a block off plate where the EGR mounts on the back of the intake? What did you use?

Cyawn

I bought the kit off of eBay for the block of and its metal plates and backfiring of the exhaust.

BSmiff

Im going through kinda the same thing. Other items ive checked so far are exhaust leaks, burnt wires, any air gaps around MAF, air filter fell off, and replaced EGR valve. Only things left I can think of are PCV valve and coil.

Cyawn

I fixed my problem man. It was my number 8 plugs. The gap was smashed down all the way so it wasn't firing at all and it made my car run like ****. My buddy helped me when I did all that to make it go faster. I knew I should've double check the plugs to make sure they were right. I finally did and found the problem. So try pulling your plugs to either see if their filed or if the gap is not right. If it's your ignition coil it would do that under load but I would change it anyway.

BSmiff

I got brand new TR6s with less than 1000 miles on them I just took out and regapped less than 200 miles ago.

Cyawn

Try the ignition coil and then go from there. How old are your o2's.

Dream321