20021sc1sz

Well, I'd appreciate any help or ideas on what is going on. I bought this 96 LT1 6 speed Z28 a month ago and nothing but problems after I changed spark plugs. It was running good before, but - no - I had to mess with it. I replaced org AC plugs w/ 110k on them and used new, same AC platinums again. I did NOT change #7 yet as it seems to be the worst one to change on my car and I had big problems w/ #2, but did get it replaced. The problem is when I decelerate , the engine backfires through what I would call the exhaust, not the intake as far as I can tell. Idle is a little off sometimes and acceleration is ok with no misses, just when I let off the gas pedal it backfires.

i can take it to my mechanic, but it has to be something I've done when changing the plugs. They all are seated and gapped correctly, and I've taken some out & put back in to make sure they were. Could a spark plug wire that was taken off at plug and put back on have got damaged from taking it off and on? I twisted the wire ends before pulling them off and did not pull on the wire alone, just the 90 degree ends of the wires. This has been a very frustrating "repair" or really "maintenance". Really don't like the way these plugs were designed by the engineers as far as location and replacement issues.
And would still having the original plug #7 in with all the rest new cause something like this? the other 7 original plugs all looked very good for having 110k miles on them, chocolate brown and still gapped correctly at .050.
Help anyone please!

cornelius107

Good chance you plugged a wire (wires) into the wrong position on the distributor. Ive done this before. Many have done this before.