97 S-10 4.3 6 cl. vortec 4x4. Hooked to computer and only missfires (only cylinder 2) when engine under load or above 3000 rpms. at idle no missfires at all. changed plugs, wires, coils, & cap. Nothing changes the missfire. even changed the post that rotates in the coils. coils should fire at -2 but are firing at -9. Could it be fuel related I changed 2 injectors a while back? If it was fuel why does it show as an electrical missfire on the computer? Could it be a sensor truck will not heat up also? Coiuld it be valves? Stumped. Engine new only 15,000 on it, completely rebuilt.