Friday, November 9th, 2012 AT 12:26 AM
I have a 99 f150 5.4. It runs fine but I have to prime the fuel system before I can start it about 5 to 6 time. I have changed fuel pressure regulator, fuel pump, fuel filter. I have also removed the fuel rail and checked the injectors for leaks but none found. What else can I check? Fuel pressure drops to zero as soon as the key is turn off.