5.4 running lean
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5.4 running lean
I've got a '97 F150 with a 5.4.
The truck started throwing a lean code. Checked the fuel pressure and it was low so I replaced the filter and got 2# back. Not enough so I put a new fuel pump in her.
Now she's throwing lean codes on both banks. Clear the codes, drive the truck for 20 to 30 minutes and the codes return. Run diagnostics while driving and the short and long trim voltages on both banks look normal.
So what's next?
Thanks,
Bass
The truck started throwing a lean code. Checked the fuel pressure and it was low so I replaced the filter and got 2# back. Not enough so I put a new fuel pump in her.
Now she's throwing lean codes on both banks. Clear the codes, drive the truck for 20 to 30 minutes and the codes return. Run diagnostics while driving and the short and long trim voltages on both banks look normal.
So what's next?
Thanks,
Bass
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Mine threw codes saying it was running lean Nd looked all over for a vacuum leak. Someone on here told mme to clean the MAF sensor and that's all it was. They make a spray for cleaning it. Have been told only to use that and not cleaners such as brake cleaner.
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From: Louisville,Ky.
Brake cleaner and MAF cleaners work good. Carb cleaner leaves a film. Just spray the filaments, don't touch. Also check the PCV hose elbows front and rear. The rear one tends to get overly soft and cracks.
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I've always heard to stay away from brake cleaner. No matter though as I've got MAF cleaner and electrical component cleaner on the shelf.
I'm thinking that this won't solve it though. The truck also is a bit hard to start. When the truck is cold, you have to engage the starter for 1.5 - 2 seconds.
I'm thinking that this won't solve it though. The truck also is a bit hard to start. When the truck is cold, you have to engage the starter for 1.5 - 2 seconds.
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Fleet Owner
Joined: Aug 2010
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From: Reynoldsburg, Ohio
Just asking a question here...............
Assuming the new pump gives acceptable pressure readings at the test point could this condition be related to worn injectors?
I don't know enough about these systems so forgive me if this is a foolish question!
Assuming the new pump gives acceptable pressure readings at the test point could this condition be related to worn injectors?
I don't know enough about these systems so forgive me if this is a foolish question!
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Sorry for not getting back. The truck's been parked while I worked on other stuff.
Cleaned the MAF sensor, no change. After clearing the codes, the truck runs for about 20 minutes before the Check Engine light comes back on. 20 minutes continuous, two ten-minute trips, with or without complete cooling between trips. 20 minutes.
Both left bank lean and right bank lean are being thrown. Both of the O2 sensor's voltages/patterns look normal and regular on the graph.
~Bass
Cleaned the MAF sensor, no change. After clearing the codes, the truck runs for about 20 minutes before the Check Engine light comes back on. 20 minutes continuous, two ten-minute trips, with or without complete cooling between trips. 20 minutes.
Both left bank lean and right bank lean are being thrown. Both of the O2 sensor's voltages/patterns look normal and regular on the graph.
~Bass
1st Gear
Joined: Dec 2021
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98' running lean
hey folks, i have a 1998 f150 4x4 with a 5.4l, since i bought it it has been running lean. (p0171, p0174) i have done everything i can think of. i have replaced the fuel filter, maf, spark plugs and coils, egr, egr sensor, pcv valve, pcv hose, intake vacuum lines. i cannot think of anything else that i can replace. if you know somthing i dont please let me know. thanks fellas.
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From: St Louis
hey folks, i have a 1998 f150 4x4 with a 5.4l, since i bought it it has been running lean. (p0171, p0174) i have done everything i can think of. i have replaced the fuel filter, maf, spark plugs and coils, egr, egr sensor, pcv valve, pcv hose, intake vacuum lines. i cannot think of anything else that i can replace. if you know somthing i dont please let me know. thanks fellas.
Start by pulling the freeze frame data and posting it. The conditions under which the code(s) set is important to know.
Well, I would definitely check the O2 sensors since they are what guides the ecm in regards to fuel air mix