okay... I have an 87 k5, stock. It's missing and bacfireing at just about any RPM. I replaced the ignition module about a mounth ago.(she left me dead on the roadside) About 2 weeks later, the missing and backfireing started. Since then I have replaced the ignition coil and the pick-up coil, oh yea, and the fuel filter. She is still missing and backfireing. I will replace the plugs, wires, cap and rotor this Sun. at that point I will do the timeing. Hopefully the missing and bakfireing go away then, but if not, dose anyone have any trouble shooting suggestions a novice but willing garage machanic can try .......