problems when starting cold engine

[2000eddiebauer]

My 2000 Explorer (V6 SOHC) has been having some problems starting when the engine is cold. Usually on the third try the engine will start, and once the car has been running it will have no problems afterwards.

What could be causing my Explorer to have a hard time starting? I had a tune-up at 60k miles - around 4 months ago and had plugs, wires, fuel filter, etc. replaced.

I had problems starting my Explorer twice in the last 4 days. The second time it was parked in my new driveway which is on a hill. My gas level was around 2/3 full. My gas level was low a few weeks ago in my driveway, and it wouldn't start until I added a couple gallons of gas to the tank (computer said I had 70 miles to empty).When I have problems starting my engine cranks strong. So I am pretty sure the battery is ok.

 

[TPLYNCH]

May be the check valve in the fuel pump. To test - Turn the key to on, wait (you should hear the FP whining). Turn key off, then back to on again and wait for FP to stop whining. Turn off, turn on, pause til whining stops, then turn key all the way to start. If the engine fires up, chances are very good the check valve is bad.