Help! engine codes-p0171 and p0174
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Elder User
Joined: Mar 2005
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From: Southern New England
Help! engine codes-p0171 and p0174
2001 5.4 Expedition 48k check engine light came on and following codes came up. p0171 and p0174.
The truck still runs great and there are no idle problems. I replaced the pcv line and elbow (read all the old posts) there was no apparent holes in the old one. Cleared code and light came back on after about 5 miles.
Mechanic thinks it may be intake plenum o-rings, as there are no apparent vacuum leaks elsewhere.
Help!
The truck still runs great and there are no idle problems. I replaced the pcv line and elbow (read all the old posts) there was no apparent holes in the old one. Cleared code and light came back on after about 5 miles.
Mechanic thinks it may be intake plenum o-rings, as there are no apparent vacuum leaks elsewhere.
Help!
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Elder User
Joined: Mar 2005
Posts: 521
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From: Southern New England
FWIW. Was the MAF (mass airflow sensor) that was causing the lean codes. Seems that Ford has had to replace so many, they offer MAF's as a remanufactured part with a core charge.
Last edited by 2Fords1Jeep; Mar 25, 2005 at 06:03 PM.
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two vacuum leaks
I was just going to post the follow up to my saga on my P0171, P0174 codes and saw yours....my 99 Expy had two vacuum leaks...both at elbows/bends on the vacuum system....I fixed both and cleared the codes with my new OBD II computer and it worked great....the vehicle also runs much smoother.
Thanks for all the help.
Milkman
Thanks for all the help.
Milkman
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Elder User
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From: Southern New England
Replacement of the PCV line was my first course of action. Unfortunately the original had to holes or splits, but I replaced it anyway. Brought the truck to my mechanic who could not find any vacuum leaks and traced the problem to the MAF sensor.
Truck runs much better (more pickup) and fuel mileage has gotten better.
Truck runs much better (more pickup) and fuel mileage has gotten better.
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MAF Sensor?...
How much does the MAF sensor cost?
Last edited by jdsmith75202; Sep 13, 2005 at 11:13 AM.
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From: Madison, NC
I also have these codes and cannot get rid of them. I have no vacuum leaks. I can clean the maf with electrical cleaner and some air and the codes will not come back til about 100 miles later. should I also be looking into o2 sensors? can they be checked? 125k miles on the engine..
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Elder User
Joined: Mar 2005
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From: Southern New England
I also cleaned the MAF sensor but it ended up being DOA. They are available as rebuilt from Ford at about 150.00. If you have access to another vehicle borrow the MAF and see if that solves the problem before you buy. Don't let anything touch the sensor filaments!!
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