NEED HELP! '91 ram need diagnostic help!

Does it have the "old style" electroinc distributor? If yes, try checking the gap for the reluctor in the distributor. I had one in my old cuda that would start cold and not warm. Turned out the gap between the reluctor and the pickup was too wide at .030". I can't remember the spec anymore, but I believe it should be .007" or somewhere near there. The gap was enough to get spark cold, but when it warmed up and the gap opened up, it would not start.

Make sure you use a non-magnetic brass feeler gauge.