Tracker won't start when hot

Maintenance/Repairs
1

I have a 2000 4d 2WD 2.0L Tracker and I have a problem that’s been going on for five years and four different mechanics can’t figure it out. When it is hot in Austin Texas during the summers my car will not start after short trips. Running errands and if I’m not in the store or where ever for 20 minutes or more the car will not start. I used to have to wait about 4 minutes to start it but now it’s more like 20. It will try to start but won’t kick over. Then last week it stalled when I tried to proceed from a stop at a signal light. I had driven about 30 miles in heavy traffic and high heat. It had never stalled before, it would only not start after quick trips. Here are all the things I’ve had replaced, and I do regular maintenance on this car- I’m big on maintenance:
7/12 Cam shaft position senor & another sensor- under the transmission
6/25/12 Fuel Pump & filter
3/17/12 Front Rotors, pads, rear shocks
3/10/12 O2 Sensor Pre-Cat, intake gasket, injector O-rings, EGR valve and clean ports
7/18/11 Ignition coil, spark plug boot, spark plugs, inspect & regap plugs
11/08/11 Radiator
It does not overheat. The AC works fine. The fuel pump was replaced because the mechanic left the car running and it turned itself off, so we thought that was the problem. Yesterday I picked the car up after the second sensor was replaced. The mechanic had been driving it around on errands etc. for two days and it worked fine. I drove it 6 miles and went into a store for about 10 minutes and it wouldn’t start. Waited 20 minutes and it started and I took it back to the mechanic. It worked fine. We started it many times and also after waiting 5-10 minutes and trying again. Worked fine. I took it home and parked it while I pulled my neighbor’s car out of my garage and next door to her driveway. I returned the keys, brief conversation and when I went to start the car to pull it into my garage it stared very rough, the car shuddered and shook and I was able to pull it away from the curb and it coughed and sputtered onto my driveway and stalled. I waited another 10 minutes and it started and I pulled it into the garage.

Please help!

2

If I were you, I would be looking at the fuel pressure regulator.
Leaking injectors is another possibility.

3

I assume that the MAF and coolant temp sensor were checked for proper readings? A poor response on these could lead to over rich starting fuel mix.

4

Has your mechanic attempted to monitor live data from the ECM to determine what the computer is seeing and doing when attempting to hot start? Sensors can have glitches that occur at certain temperatures, some sensors can totally blank out at specific temperatures.

5

Along with the direction VDC is heading into, what happens when you floor the gas pedal while starting it?
If it is flooded, it will not pump fuel when you do that so may clear the flood condition.