1992 Ford ranger cranks up fine runs untill it gets warm

Check your codes, you have a codes system on this truck called EEC-IV. If you have a bad MAP Sensor or bad coolant sensor, that will foul the plugs. Also, check fuel pressure, it should be about 40 psi. I have seen the fuel pressure regulators wear out and cause flooding as well. Now, you are dead sure that you have spark, at the plugs, when it will not start? I ask this because I have seen a lot of ignition components go on these trucks ( I used to be a Ford DealershipTech ) and when they get hot, they do NOT work. So, more food for thought.

sound like a bad coil even if it has spark at first it can lose it when its hot..