C-6 Cuda

I have a conversion 2005 C-6 auto Z51 package in a restomod. problem i have is. when started it will misfire under medium to heavy load. more violent as load increases. if i restart right away the misfire goes away. i have HP Tuners to eliminate VATS and the #2 O-2 sensors as i have headers, otherwise all stock.
Additionally, when put into drive. it starts off in second gear not first. i can manually shift into first and it seems ok.
no codes showing in HP tuners. Any ideas ?

Thanks Larry

z06clif

Are all the wires at the plug and injectors on secuely~

Clif

dpigguy

This ^^^^^^^^^^^^^^^

C-6 Cuda

Thanks for the reply. Yes plug wires on and tested prior to installing new plugs. also tested injectors. all good. in fact if they were not, it would not run properly when shut off and immediately restarted. This occurs every time I start it after sitting for a short time. trans not starting in first is another issue of course.

reasonable suspicion

Battery good?

C-6 Cuda

Yes Battery is good 12.5 V 14.V at idle

C-6 Cuda

Really need some help with this one. it has me completely baffled

sikhs.2

I'd check the porcelain on the plugs, they can get damaged during a header install. Look for fine cracks.

trebor8008

Misfire? One cylinder or multiple?