Intermittent Problem Starting

2001 Windstar with about 90,000 miles.

There have been 4 occasions in the last 5 months or so when the vehicle will not start after having been driven for awhile. On the first two occasions the wife called and I went up to look at it (~ 1/2 hour trip.) When I got there it started fine. Third occasion it didn't start after fooling around with it for a couple of hours. Had it towed but the shop could not get it to repeat (started fine for them) and they weren't able to determine anything and presented me with a list of expensive potential repairs. Last occasion, didn't start after about 3 hours so left it overnight and it started then.

Initially when trying to start the van it fires, hesitates, struggles and dies. After a few times of that, it just cranks and doesn't fire. Cranks fine.

Haven't done any ignition work on the van. Still original plugs, wires, and cap. Would appear to have something to do with a warm vs. cold engine. But, obviously, it happens infrequently. Many short trips are made with no problem.

Any suggestions would be appreciated.

I am no mechanic, so these are just off the wall guesses, but....I have a 2001 Windstar Sport with 3.8L

1) Have you tried the P0174 fix? Anyone who own as Windstar must do this fix at some point and depending on how bad the vacuum leak is it can cause all kinds of problems. There could be a lot of oil sucked into the EGR system as I have seen in my own.

2) Could be a loose vacuum hose on the EGR system (not sure if this would keep it from starting though?). I found one hose almost falling off when I did the P0174 fix at the back passenger side of the clamshell

3) I have had times when you turn the key and the van won't even try to turn over. My first thought is dead battery when it happens, but it always turns out to be the alarm system has disabled the ignition. To fix it, I just trip the alarm and then turn it back off and then I am back in business. I have also fooled around with the alarm light on the dash but I am not sure what effect if any that has on the alarm? Maybe someone else knows?

4) The fuel pump could be on its way out. I have a F150 that wouldn't start very easily (intermittent) and until I could get it repaired, I just took a 2x4 and wacked the side of the fuel tank hard (drivers side) and this seemed to get the motor in the pump to move just enough that it would start again. Not sure what the Windstar has for a pump, but it is probably the same set up. The pump seemed to act up the most on warm days and was a problem around 85,000 km. Turned out the pump also has a suction screen on it and that was covered in varnish from the fuel which wasn't helping either. The filter was not in great shape either.

Beyond that I have not much else to add.

Flakey relays I would guess. PCM power relay most likely, and pump relay perhaps.