after installing heads, cam, intake, tb & headers on my 98 WS6, it seems as though a coil pack is out. It was backfiring like crazy until it just would die. I swapped coil packs with a buddy that has an 01 Formula and now, the car runs great. The problem is, now he needs his coil packs back! Is there a way to tell which coil pack is bad? Does this routinely happen when moving from a 98 head to a 99+ head like the prc 2.5r heads?

 

hook up any of the diagnostic programs and see which cylinder has the histoy of missfires.

 

you could pull plugs wires and crank the no see if it arcs. if it arcs you should be good on that pack. just go through them all you should be able to find the bad one that way

 

Swap him back one side at a time. Narrow it to one side, then do individual tests with one of his coil packs until it's fixed.

 

if you have a timing light, hook it up and you should be able to tell fairly quickly which one is bad

 

That's a great idea.

Only problem is nobody with an LS1 owns a timing light!