bj31600001

The truck is a 03 f-150 with 45000 miles on it. I think the fuel pump is going out but it doesn't have a lot of miles on it. But here is what led up to the problem. The gas would get low and I would put gas in it then it would run fine til I turned it off. The next time I would try to crank it it would not start. It acted like it wasn't getting enough gas. So I changed the fuel filter and it would run fine til the gas got low then the same thing. I would change the fuel filter and I haven't let the gas get low enough for the fuel light to come on. Then the other night with plenty of gas it started running pretty bad, like it wasn't getting enough fuel, so I pulled over and turned it off. Then it wouldn't crank again. It acted like it had previously before I changed the fuel filter. It sat where it was at for a day or so before I could get to it to fix it and when I got to it cranked just fine. I ran a diagnostic test in it and it came up with codes P0174 and P0171. I know it could be a plethora of problems so anyone who has any ideas or experience with this sort of thing please leave some advice.

Thanks Brodie

torkum

The most common for the codes is a tear in the PCV hose elbow. The fuel delivery problem could be trash on the "sock" [the pick up filter in the tank] but first I would do a fuel pressure reading before dropping the tank to check the filter.
What motor do you have?

bj31600001

I have the V6 and I checked the pvc valve a minute ago and it was fine.

torkum

You probably have the intake leak problem because you have a 4.2. Do a search on intake leak codes P0171 and P0174. Several good write ups on the subject.

Good old Bill

By doing my own work, I'm probably fussier (spelling) fussy. Any way by not having to spend money on labor, I go after problems faster then others. I would get check engine lite and codes P0171 & P0174 on cold morning startups. Never had any other associated problems. Replaced the bolts/grommets and seals per the TSB. Check this site; search.ebscohost.com
USER: greatfalls
PASS: publiclibrary

Select auto repair, year, make and model

The TSB has been revised 2 times since original. I fixed my codes, but again never had any other problems, think I repaired it before things got worse. My 02 4.2 has 182K and runs fine.

bj31600001

Before that last post was up I removed the air filter and noticed a tiny leaf setting on the MAF sensor. I removed it and then tested the codes again and got none. The check engine light went off too. I am going to drive it around for a bit and if anything else happens because I doubt a MAF sensor can make the truck rin so horribly.

Good old Bill

Way to go, hope all is good.

bj31600001

I checked out that web site. Its pretty awesome.

mechman072

One thing to look at on the V6, is the heated PCV system. If your truck has one, had the same problem on mine. Vacuum leak where the line connects to the throttle body. Dealer item only though. Replaced and reset codes, no more problem.

06fordf150

could it be the sending unit going bad maybe