1994 Ford Ranger 171,000 4cy. 2WD

So far an intermittent problem. (5 times in 3 weeks). Engine rotates but will not start. This occurs after vehicle has been driven and parked for 15-60 minutes. Sometimes will start after waiting a few minutes and sometimes it takes more than a few at which time I start checking wire connections and sweating profusely. So far there has been no detectable reason for it not to start or to start after not starting. I have tried to pump the gas on at least one occasion (usually starts without this) and smelled where it was flooding so I know it is getting gas. When it does not start it sounds like it is not firing on any cylinders. (That would seem to be significant on a dual ignition system).