1998 Mazda 626 Engine quits after warming up

I would be able to restart after a wait of about 5 mins. Ignition was firing when it would quit. After it would stall, I could hear the fuel injectors resetting with a clicking noises coming from them.

The check engine and the red door/key lights would lilluminate when stalled. Yet, it would still leave no codes. After waiting and getting a restart, if the red light along with check eng. Would remain off, the idle would be reliable and steady allowing me to take off and drive for a short way (1 mile). It seems that the warmer the day and the more I stop and go, the more likely it is to die.

Driving at higher speeds (40mph +) seemed to give me more driving time before stalling. I do not know how to check for fuel flow. The checking we performed earlier (codes, etc.) Were done at a Mazda specialty shop (not dealer) he fixed all my vacuum leaks but failed to resolve my problem.

I forgot to add that we had changed out both engine relays. No change.

I don't know if the mech had checked for fuel flow. But the engine sounds like it is leaning out when it dies. Knocking sounds as the rpm's die off. This is what that factory recalll was for, requiruing ecu re-progaming.

It will run longer at freeway speeds with a higher fuel demand than at stop and go city driving. Things don't add up.