My son’s 07 Camry sometimes will not start after an hour or so of driving. It turns over and tries to catch, but won’t idle. After a 20-30 minute cool down, it will start. However, if you run it 5 to 15 minutes, it has no problems. The first time it happened, the check engine light indicated a fouled #2, so I replaced the plugs and coils. It happened a second and third time after I drove the car to his home town to give to him, but no check engine light these times The weather was moderate, no rain.
Have the residual fuel pressure tested.
The residual fuel pressure prevents vapor lock when the engine is turned off when hot. If the residual fuel pressure quickly bleeds off when the engine is hot, the fuel in the fuel rail(s) boils causing vapor lock.
This then makes it difficult to start the engine.
Thanks for your advise. Is there a owner serviceable port to connect a pressure gauge? If so, do you know where it is?
I believe you have to use a TEE adapter at the fuel filter.
Another possibility is that you have a leaking fuel pressure regulator. This is connected to the fuel manifold and has a line to the intake manifold. When the diaphragm leaks the fuel escaping goes directly into the intake manifold. One way to test for this is to put the throttle pedal to the floor and crank until the engine catches. The second way is to do as 'TESTER" recommended and test for the residual holding pressure and see is if it drops over time.