No when you say it won't turn over to start do you actually mean that it cranks and won't start? Like it cranks like it's trying to turn over but it doesn't catch and actually start up?
If so, I doubt it's a leaky fuel line, clog or spark plugs.
In order for an engine to run, it must have spark, fuel and timing. If one of those isn't there, it won't start or it will die. A leaky fuel line, clog or fouled spark plugs will give you a more consistent symptom than the intermittent problem that you are currently having.
I common problem on those vehicles (that will cause a cranks won't start condition, intermittent) is a faulty PGM-FI relay, also known as the Main relay. This relay controls the power to the fuel injectors and will normally fail when the ambient temperature is warmer outside, I've seen them fail at all sorts of times though.
That's my own personal thought, but it could be anything and it will have to happen more frequently in order for somebody to do other than guess at the problem.