Toyota Repair: hot start problem with 91 4x4, toyota 4x4 pickup, air flow sensor

Question
I recently purchashed a 91 toyota 4x4 pickup. it has a 22re fuel injected engine.When it is cold motor starts up and drives fine. after driving for half an hour or so, motor will not start. It fires up for a second and then dies.leave it for an hour or so and then it fires up. I checked the resistence on the circuit opening relay under passenger side kickpanel. didn't test to specs so relaced it.same problem. Changed the air flow sensor as it wasn't opening when the ignition was turned on. same problem.I have scanned the whole system and everything seems to check ok.I am going to test fuel pressure hot and cold tommorrow. Could the fuel pump be the problem. I'm running out of ideas.


Answer
The problem may be the cold start injector time switch, if it's bad it can turn on the cold start injector when the engine is warm and flood the engine, the cold start injector may be leaking, also check to make sure there are no leaks on the intake system between the air flow meter and the throttle body. Another item to check is the ECU temp sensor.