I have an 88 f150 with the 5.8L, single tank. Since the temps have gone up it appears to have a vapor lock problem. I can drive it 20 to 30 miles before it starts to have any problems. Motor temp isn't bad but its between 1/4 and 1/2 up. Today I put a pressure gauge on when it first died and got about 5 psi. Let it cool off until turning ignition on netted 40+ psi, then started and ran fine for about 15 miles. Now after sitting for 15 minutes it'll run about 2 miles. Since I'm still about 8 miles from home its going to be a long afternoon in 110 heat. Will changing a fuel pump have an effect and which one?
Before u assume its a vapor lock or fuel issue I would try and getting your ignition coil tested my moms just went out in her jeep it will run good for a while then cut off completely for about 2 hours than crank and run.... So check that and get back to me.
The coil, TFI, Stator, MAP sensor, and fuel filter gave all been changed recently. As stated in my post I get no fuel pressure at the rail when it wont run but I hear the pump run. I replaced the pump in the frame rail yesterday, but no difference. I could go ahead and replace the in-tabk pimp as well, but would rather not if that's not the problem. We do have alcohol added to the fuel here in Arizona, us there another addative I could use to raise the boiling point?
Sorry I seemed to have dropped off the face of the earth. My Droid app didn't tell me there were new replies to my post. As far as the pimp goes, my Droid is a dirty minded little thing and keeps changing what I typed to what it wants to instead of what I meant. I guess I shouldn't use it for looking at ****.