94 Explorer runs rough on warm restarts


#1

I have a great running engine until I need to restart it soon after shutting it off. It will try to run, but very rough. It will not respond to the throttle either. after a few tries over about 10 minutes it will start and run normally. I have changed the plugs and wires, no improvement. Old plugs were all a nicek light almost white color. Car has 110K miles, does not use oil. Where do I start.


#2

Fortunately checking the fuel pressure on this is only slightly more challenging than checking tire pressure.

There might be a leaking injector or the pressure regulator thats flooding a cylinder or cylinders.

Make sure it holds pressure with the engine off.


#3

The fuel pressure regulator valve seat can wear on these and cause this problem. This can cause a vapor lock situation because the pump only turns on for 5 seconds until the engine starts. Turning the key to ON about every 10 seconds 4 times before starting the engine can usually clear the bubble. You could invest in a new fuel pressure regulator for about $60 since there is no way to test this item. Disconnect battery after replacement to reset the computer so it learns the new regulator.