Sounds so obvious, but, check to see that all the plug wires are fully seated down on the distributor cap. I had a plug wire that wasn't staying on the distributor cap....it would slide up out of the slot because the rubber cup was not in the right place.

Good luck!


Bernard Laiben
1951 3100 Chevy Deluxe Pick-up (original with 73,000 miles on a "straight Six" 216)