one of my friend's has a 03 that wont start, It has fuel to the filter head, He said he had it running and it quit, it does have fuel in the tank, I did notice that 1 of the injectors looked like it has been leaking fuel, ( 1 st thought air intrusion?) he said that since he started having trouble that all of a sudden his fuel gauge has started acting crazy. any help would be much appreaciated Thank's Mudguts.

 

If the fuel gauge is acting crazy, my first suspect would be the pump module. Get a fuel pressure gauge on it and see if he's getting good pressure up to the injection pump.

Has it thrown any CEL codes?