Almost ready to give up. Explorer would not idle when cold (LOW idle but no 'missing'). Replaced both O2 sensors, the MAF sensor, Engine Coolant sensor, IAC valve, new TPC, new plugs, new wires....and when I leave the battery unplugged for 15 mins and rehook...for 2-3 days it runs great! But then the problem comes back. When the engine is cold, she idles below 500 rpm (hits on all cylinders) and dies. I rev it up a time or two and it comes to life. If I drive her 5 mins and park...I hear the fuel pump run, but, she still won't crank right up. she spins and spins before she cranks...and if the engine is warm, she's a normal idle. Someone suggested the fuel pump (28psi) is letting fuel 'leak back' to the tank. Will that cause a low idle? I thought fuel pump would either pump or it wouldn't....again, its a LOW idle when cold and thereafter its a slow crank. I 'can' coax it by turning the key to let the fuel pump run, then when it stops, I turn the key off, then back on and the pump runs, then back off...and then it fires right up.

Any advice?
AF Lt Col