Expedtion starting problems

I am having a starting problem with my 97 Expedition with the 4.6 L.About once a week the vehicle will not start. It sounds like the motor is flooded, but the acclerator is not pushed down. The motor simply won't roll over. If you let it sit for a few minutes it will start right up. I have had diagnostic test run from 2 mechanics and the fuel pressure is fine. I have replaced the battery, plugs, wires, various sensors that were reccomended and cleaned some of the air intake parts. If anyone has any suggestions I would greatly appreciate it. Thanks

Does it crank and not fire? I know that on my 99, if I park nose down on a slope with less than a 1/4 tank, my Expy will act like it's out of fuel. Warm or cold engine doesn't matter.

If it doesn't crank with a charged battery, I'd look at the starter or the solenoid.

If it cranks but doesn't fire, I'd initially think it was a fuel distribution problem first (pump, regulator, injectors, cut-off switch), or fuel quality problem. Rule out those, and next I'd look at a firing problem (coil, wires, plugs) or logic problem (CPU, relay, timing, etc.).

1999 Ford Expedition XLT 4.6L
2003 Volvo S80 2.9L