theman637

Guys I could really use some help. I've got a 99 SS I'm working on for some ppl, they installed a new m6 trans and some off brand longtube headers that look like they are made really good. when they brought me the car it was backfiring like crazy more at idle and when I reved real fast, so I figured it needed a tune but they wanted a new cam and springs installed and the egr delete and all that stuff before I tuned it. after I get all that done and load the the tune with hptuners that I had from my dyno tune that had the same specs all but the header brand and it still backfires, it shows no codes I've changed all the sensors twice checked all the grounds,pink wires, intake leaks, exhaust leaks, moved coil packs,plugs and wires, fuel pressure, timing, new fuel about anything you can read about on any forum I've tried and nothing helps the funny thing is if I unplug the driver side coil harness it stops backfiring and doesn't change the way it's running but unplug the pside and it pops a few times and dies Dside header runs much cooler then Pside after ten mins of idling you can touch the Dside still I'm down to thinking the computer is junk but it runs perfect and has good power anybody have more ideas cause I'm lost.

lsxsleeper

If you can touch the header after 10 min those cylinders can't be firing

lsxsleeper

Pull the plugs on the cool side leave wire attached start car and look for the arc

Majestic9C1

iTrader: (19)

the coil harness on driver side sounds like its dead..