squashc6

I have a cammed 2005 c6 z51 that is only backfiring at idle.
I have changed the plugs twice,new o2 sensors, plug wires, injectors cleaned, new wiring from o2 sensors back up to the injector wiring. The car is completely straight piped with American racing headers. Any ideas on what could be causing this? Vacuum leak?

baxsom

Did it just start or has it been backfiring since it was cammed? Almost sounds like the
timing chain was off a tooth

squashc6

The backfiring was happening before I cammed it. Started happening once I broke a ground and had a spark plug break off in the head. But I have fixed the ground and had the head helicoiled so both of those problems have been fixed.