Help, here is my problem, I have a 84 5.0 with 4 barrell carb, anytime i try to creank and the tach does not move car will not crank, If it does Move car cranks right off runs like a charm, i can go a million miles if i want to, the only thing is, when i cut off and wait about a minute to crank tach won't move and car will just turn over, but if i crank again immediately after cutting off car cranks fine. I have already changed coils, modules, and the plug wires several times, nothing seems to help. Any Suggestions?