I just bought a 1990 F.150 4x4 with a 5.0 efi. The truck is very,very hard to start all the time. Also all of the time if I give it more than a quarter throttle, It falls on its face. No acceleration, and just runs like crap. It has good cap, rotor, plugs, wires, o2, pcv valve, fuel filter, and air filter. The only way to start the truck is to turn the key about ten times for fuel and crank repetedly. Any body had this problem ? Please help a.s.a.p. as this is my daily driver.

 

Check the fuel pressure and volume yet?

 

I have hit the bleeder valve on the fuel rail and there is very low pressure, nothing like my 5.0 mustang. I just replaced the rusty and leaking gas tank and I know that the fuel pump is extremely noisey. Could possibly the fuel pumpbe loosing pressure as it is becoming old. would a new pump fix this problem. I am a body man at a local chrysler dealership so changing parts is know problem, i just want to know what to go and buy. low fuel pressure sounds like a possible cause.

 

Also I forgot to mention it has a stock catalytic converter with 125,000 miles on it.

 

If I hit the bleeder valve no gas or air will comeuntil I hit the key about ten times. Then it has gas and will start up. But it still falls on its face all of the time. When it is running it has descent pressure and there is no change in pressure if you unhook the vaccum line.

 

What is the pressures running? What does the pressure do on WOT? Pressure should increase on acceleration. How long does the pressure hold after you shut it off? Pressure should not drop more than 5 psi in approximately 10 minutes.