Engine turns, tries to start, but shuts of emediately on 2002 Ford F-250 Super Duty

After engine warms up and running, not always, but has done it three times, u turn the key, engine turns tries to start but quits, no codes on scanner, i replaced the Idle Air Valve, but did it again. Fuel filter is 6 mo. old. Also having hard time locating the fuel pump relay.

by in Bradenton, FL on February 15, 2011
2 answers
ANSWER by on February 15, 2011
sounds more like a fuel pump. have the pressure checked and i bet you will find little or no pressure. Roy
ANSWER by on February 16, 2011
THERES AN INERTIA SWITCH ON FORDS THAT SHUTS DOWN THE FUEL PUMP ALSO. IT ALSO SOUNDS LIKE A THEFT DETERRANT SYSTEM HAVE YOU CHANGED KEYS RECENTLY