I have a 96 F-150 4X4 5.8L, dual tanks. I'm getting codes 171 and 174. I've changed plugs and cleaned the idle conltrol solenoid. It is hard starting when cold. No real performance issues. I'm thinking a fuel supply issue. I have a new fuel filter but can't get the old one out due to it being tucked up between the tank and frame. I can't get anyone to help me figure it out. Both O2 sensors could be faulty but not likely. Idles a little rough after it warms up. Haven't checked for vacuum leaks other than a visual. What kind of fuel pressure is supposed to be in the fuel rail after the engine has cooled off. I haven't checked fuel pressure but would like to before I change the filter and again afterwards. has 105,000 miles. Had 84,000 on it when I got it, so who knows what has been done to it.

I'm about ready to pull my last hair out. I'm already bald. Please help.

Tony

 

Tony,

We had a 96 f150 in at work last summer and it had the same issues, hard start and after idling for a while it would suddenly die. All of us mechanics made our predictions and got the ok to repair what we thought it was. I myself figured it was the faulty fuel pump, which was burned out due to years of use. We replaced the fuel pump and also cleaned the idle control solenoid along with chekcing for vaccum leaks. About 3 weeks after battling this problem we decided to take the tanks out again and check the fuel pump we had replaced which was burned out. After one of my coworkers accidentally dropped his side of the tank fuel spilled all over the floor. We noticed it was extremely dirty fuel and decided to check the other tank. We also noticed on the bottom of the second tank there was dirty fuel. We emptied the tanks and put new fuel in it and it ran like new. Check your tanks. You say you think it may be fuel supply issue, try looking at the fuel source itself because that old fuel being mixed with new fuel may be corrupting your fuel supply. I could be totally wrong, but it is just a place to start. Check it out.

Nick