I got a 85 Firebird 2.8L V6.. About a month ago it started popping through the intake manifold. I have replaced plugs,cap and rotor and fuel injectors. Ran good for like a day.. then it started again.. maybe its the timing that jumped idk.. Now it wont start at all. I have no idea wuts wrong with it.

 

check you coil distribator mod and pick up coil.

 

Just a suggestion...hope its not your problem but I have an 83 that was backfiring through carb and tried everything I could and finallly got some advice that the cam may be bad, I tore it down and sure enough one lobe was completely round. It started off just backfiring at certain rpm but got worse and worse.

 

Yea my cuzin said the same thing.. I already have the engine have way taken apart to do timing.