I have a 94 Explorer with the small V6 and about 65,000 miles.

About a month ago I began experiencing intermittent starting problems. Engine would start and run at sub idle. Any attempt to increase throttle would cause motor to quit. Generally shutting down and restart would be successful. Sometimes a shift to neutral would seem to help.

Before this problem started, we performed a tuneup (sparkplugs) and replaced the Mass Airflow Sensor and this directly solved a general performance problem - some detonation at freeway speeds and resulting check engine light. After this work, the truck ran well.

Last week, on the way to work in the morning and about a block from the house, the motor quit and would not restart. Over a period of a few days I would try to start the motor and would get a sub idle run condition that seems like not enough fuel or improper timing although it seems too smooth for timing. I checked ignition at one plug and have good spark there.

I have changed the fuel filter and the fuel pump relay. I have about 42 psi at the fuel rail with ignition switch on prior to start. Once running at this sub idle condition, fuel pressure drops to the low to mid 20s psi .

Should it maintain 40+ psi at the fuel rail when running? The motor sounds like it is suffocating. Does this sound like a fuel pump problem? Anyone have any other ideas?

Thanks,

AZMike

 

It may be the fuel pressure regulator , But from what you describe it sounds more like a fuel pump dying . It seems a lot of the electric fuel pumps Ford uses only seem to run to maybe 60 to 80K miles . Check the regulator first for leaks once you remove its vacuum line .

 

 

Try removing the vacumn hose to the fuel pressure regulator when the engine is running, that should cause the pressure to increase and run better. If not any better, fuel pump dead like paul said. If runs the same and pressure not increased, regulator bad.