ok on my 05 ss s/c with 53k miles, just did a few mods to car, 1.9 rocker arms, 3.25" s/c pully, throttle body spacer, 3" down pipe...ran fine for a day then got a cylinder 4 misfire changed spark plugs, swapped injectors, swapped spark plug wires, checked all wiring i removed for rocker arms...and now im STUCK! still cyl. 4, what else can i do?? Cant see the piston going bad its only got 53k, maybe ignition module? but i got spark(held plug to block) any help is appricated.

 

do you have a tuner? are you throwing KR and it's failing?

 

yes have HP tuner, no KR at idle, 2-5 at about 3k rpm in gear, 0 in park any rpm

 

Well I hate to state the obvious, but....swap coild in a dif order on the ignition control module, if the same cylinder is misfiring then its the ignition control module, if it moves to the other bank of cylinders it is the coil(unlikely)...I had this happen on my 00 ss..Worse comes to worse check the compression on that cylinder and also make sure the injector is firing using a noid light