I have a 88 F-150 4.9 that sometimes starts and runs fine, sometimes won't start at all. I am a begining mechanic with these fords but here is what I know... The truck sat for a year so I changed the plugs cap and rotor. Checked fuel pressure and it is within specs, cleaned the injectors. Put on a spark tester and I have intermittent spark and of course it runs when spark is provided. When I can get it to stay running I let it get hot and keep my eye on the spark tester and once hot the spark gets intermittent and then once off it won't start or at leastthe spark isn't steady. I am not sure where the EEC is so if anyone knows please teach me (my book isn't helping me much) I have done the coil with no luck. Any info would be appreciated. Like I stated this is not a fuel problem, sometimes it feels like sparking and sometimes it doesn't Please help! I,m supposed to drive 1500 miles next week! Oh yeah the module looks brand new

If I recall correctly, back in those days when your Ford was built, there was a issue with the electronic module in the distributor and the heat problems you described. A clue?

Wished I could be of more help!