I have a 1990 Lincoln with a 5.0L engine. It would not start. I tried starting fluid and still nothing. Checked the fuses ad computer modules under the hood, all was good. Hooked up a timing gun ad it didn't light. Took the distributor apart twice and the same result, no spark. Replaced the primary wire with a spare from my shed. Still no difference. Cranked it one more time, still dead, then the timing light finally lit and the engine started a second later. Obviously, I have an intermittent condition. My experience in electronics is they are the toughest to find. A complete failure is much easier. Sure much harder working o cars these days. The computer and smog controls call for so much equipment. I will soon be replacing this car as I am certain it doesn't have much time left. 278,000 miles without too many problems other than power windows, power seat and air suspension. Open to suggestions as to where the problem resides.