Any suggestions car stalls during idol and also while driving or stopping

What is your question?

I have changed water pump/computer/fuel injectors(all)/fuel pump/fuel tank/filter/tune-up/fuel relay/disconnected anti-theft..and still the car stalls. It is running fine now that it is winter. However once the warmer weather gets here...back to the stalling. I have even disconnected the relay for low coolant but that still does not make it start. It seems to be an overheating relay of some sort. Rad levels are up. Any ideas...it is driving my mechanic nuts and my wallet to the poor house. It is a very ghostly issue..Thanks Amy