Intermittent starting problems

I have a 1994 Ford explorer that has recently developed a starting problem. The starter motor turns the engine and you can her the fuel pump running but the engine fails to start.Problem is not consistant and sometime it starts without a problem. Anyone have any suggestions?

Does it seem to do this more often when the humidity is up?

I think that it would be safe to say that going thru dew-point has got to be part of the equation. I might add that shortly before this problem showed up that the engine got hot enough to expell the excess cooling fluid from the reserve tank all over the engine compartment. It ran realy rough for about 3-4 minutes and then seemed fine. That was on the Thursday. The starting problem exibited itself on the next Tuesday morning. If it going to run its usually in the afternoon. I hope this helps you and thanks for the reply

D Raymond