Frustrated 01 xlt 5.4

[Joseph Tator]

Hey guys, I have grown frustrated and I have tossed around a ton of cash on this truck. I keep getting a p0171 and p0174 codes even after replacing damn near everything that I can think of. First I replaced
1. All 8 plugs
2. New wires
3. New boots
4. All O2's up and down stream
5. New intake manifold
6. Water pump
7. Replaced a bunch of vacuum hoses and radiator hoses
8. New fuel cap
9. New MAF sensors

I think that's it. I love the truck and it' really clean with NO rust and I live on the water in long island so that's impressive. Any ideas or past experiences that can help my situation? Thanks all

 

[Rich_007]

New to forum and learning, after reading, those codes say both banks lean. looks like your actions all addressed the the "too much o2" side of it. What about the "not enough fuel" part of the deal? Fuel filter or injectors restricting flow? going to watch this thread and learn. I got an 01 5.4. Let me know if there is anything I can check on mine that would help.

 

[deweysmith]

I would dive into the fuel system. Injectors, fuel filter, and fuel pump are my suspects, in that order.

 

[Rich_007]

I just had a fuel pump put in mine two days ago. Live in an apartment so i couldn't do it myself. Had mechanic do it for 530 out the door. pump, labor and some sending unit. Mine wasn't throwing any codes. It just wouldn't start up. Not sure if the pumps have diminished capacity over time or they just stop working. One of the old timers on here will weigh in and answer that. When I was reading up on those codes, they said "unmetered air" was the usual culprit. Meaning its getting in after the MAF. They said the intake gasket leaking was the prob a lot, but it sounds like you ruled that out. I saw a post on here where a guy sent his injectors somewhere and they tested, cleaned an retested. Sent him a chart showing difference. I will try to find it and post the link here. Inline fuel filter is cheap to rule out, (sometimes the lines are a ***** to disconnect).

 

[Rich_007]

if you can get ahold of a pressure gauge you can do a quick check on the fuel rail. That may rule out the pump having diminished capacity.

 

[Bedrck47]

Read the attached link

http://troubleshootmyvehicle.com/ford/4.6L-5.4L/troubleshooting-p0171-and-p0174-page-1

 

[RonB1964]

What are the RPMs at idle? Is there a noticible miss when the engine is running? What is the fuel pressure? Double check intake installation and debug all vacuum lines and vacuum controlled devices for leakage. Smoke test and vacuum leak down tests may help. One thing we used to do is block off suspected vacuum ports and check for idle speed difference. Also a can of carburetor cleaner can be sprayed at the intake gasket areas for idle changes. Good luck!

 

[Joseph Tator]

What are the RPMs at idle? Is there a noticible miss when the engine is running? What is the fuel pressure? Double check intake installation and debug all vacuum lines and vacuum controlled devices for leakage. Smoke test and vacuum leak down tests may help. One thing we used to do is block off suspected vacuum ports and check for idle speed difference. Also a can of carburetor cleaner can be sprayed at the intake gasket areas for idle changes. Good luck!

No noticeable misfire, rpm at idle is 600 steady. I will have the fuel system checked out. Your advice is Much appreciated

 

[Joseph Tator]

I would dive into the fuel system. Injectors, fuel filter, and fuel pump are my suspects, in that order.

Great idea, I will check them out. Thank you

 

[Bruce Mitchell]

I had the codes for both banks lean. Had the fuel filter changed, cleared codes, been good to go for the last year or so; approx 10K miles.