I have to figure this out quickly, the race is a week from friday. First let me tell you I am a mechanic, so this is a weird problem I haven't encountered before. My care pings and hesitates when I floor it at higher speeds, say 45 to 70 mph. I have checked everything I can think of and now wonder if the computer may be bad. The oxygen sensor, knock sensor, fuel pressure, air filter, timing, plugs, wires, injectors, everything. Please if you know help me.
Check your vibration dampener for the ring slipping. Your timing may be off if it moved on you. It sounds like a timing problem.
Try running without the knock sensor disconnected, and try with the set timing pigtail unplugged and see if it acts differently.
If you had a bad plug wire, it might crossfire to an adjacent cylinder inside the distributor cap. Moisture inside the distributor cap would cause trouble too. Have you washed the engine lately?
Does it rev OK in neutral?
I have thought it was a timing problem from the start, but I have checked the harmonic balncer and it is in excellent shape. I had a bad knock sensor and I replaced, that helped a little. With the timing plug disconnected it loses its advance and doesn't run well, but it doesn't ping either. I replaced the wires and I have them spaced as far apart from each other as possible. It is most likely the computer in my mind. Does anyone know how tto check them? I appreciate you ideas and help so please keep them coming.