Turnes over, won't start

99 taurus, it turn’s over but would not fire. Then it started and ran fine. I changes the plugs, wires, fuel filter, added fuel injector cleaner to the tank, sprayed the MASS, changed the air filter… then a few weeks later it happened again what now?

Had a similar with a Toyota. Check out your distributor cap, it might be cracked.

I am leaning more towards a power supply problem to the fuel pump or a intermittent problem with the pump its self.

If the pump system checks out you may have a heat sensitive ignition part.

When the car fails check and see what kind(if any) spark you have.

You have done most of the first-step things (tune up, and routine maintenance) that we usually have to remind people to do who have a start or performance problem. Now, we need some more basic stuff: finding out if the problem is based in fuel, or spark.
piaf516 and oldschool ask you to check the spark circuit. We, also, need to check fuel. Spray a Starting Fluid into the intake tract. If it then starts, runs a few moments, then stalls, the problem is fuel (supply,or injection). Results?

Thanks guys, i will look at all the ideas.