P0171 code
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P0171 code
'98 Exp, 4WD, 5.4L, 72k miles
My Exp is getting a P0171 code (bank 1 too lean). The Exp runs PERFECT!
10k miles ago, I got P0171 and P0174....I sprayed the Mass air sensor with electronic aerosol cleaner and erased the codes.....no problems since....until now
The Exp still has the orig. spark plugs.
Any idea's what is wrong this time??.....Is bank one the pasenger side of the engine?
Mike Mulhern
Scottsdale, AZ
star8@***.net
My Exp is getting a P0171 code (bank 1 too lean). The Exp runs PERFECT!
10k miles ago, I got P0171 and P0174....I sprayed the Mass air sensor with electronic aerosol cleaner and erased the codes.....no problems since....until now
The Exp still has the orig. spark plugs.
Any idea's what is wrong this time??.....Is bank one the pasenger side of the engine?
Mike Mulhern
Scottsdale, AZ
star8@***.net
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Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
P0171 code
Hi wheezer99 and welcome to FTE 
I had an Expedition today with a similar problem other than I had a code for both banks lean. The problem with this one was it was missing bad which sends too much air into the exhaust which sets the codes. Replacing the spark plugs and 2 wires cured it. Without monitoring the O2 operation with a scan tool it's hard to tell if the sensor is working properly or not. Seeing that it's just one sensor that's showing a problem you could just have a bad sensor.....unless the engine has a miss or a vacuum leak or something like that on the 1 bank.
Yes bank 1 is the passenger's side. The side of the engine with #1 cylinder is bank 1.
With your mileage I think I'd start by installing a new set of Motorcraft plugs, replacing the fuel filter, unless it's been done recently, cleaning the MAF again then clear the codes and see what happens.
I had an Expedition today with a similar problem other than I had a code for both banks lean. The problem with this one was it was missing bad which sends too much air into the exhaust which sets the codes. Replacing the spark plugs and 2 wires cured it. Without monitoring the O2 operation with a scan tool it's hard to tell if the sensor is working properly or not. Seeing that it's just one sensor that's showing a problem you could just have a bad sensor.....unless the engine has a miss or a vacuum leak or something like that on the 1 bank.
Yes bank 1 is the passenger's side. The side of the engine with #1 cylinder is bank 1.
With your mileage I think I'd start by installing a new set of Motorcraft plugs, replacing the fuel filter, unless it's been done recently, cleaning the MAF again then clear the codes and see what happens.
Last edited by Racerguy; Mar 8, 2003 at 11:42 PM.
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P0171 code
I know this sounds basic, but you also want to check for exhaust leaks before the o2 sensor, and vacuum leaks. You should also check your pcv and make sure the egr valve is not leaking by when closed and make sure the oil dip stick is seated all the way.
jk
jk
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P0171 code
Originally posted by Racerguy
Hi wheezer99 and welcome to FTE
I had an Expedition today with a similar problem other than I had a code for both banks lean. The problem with this one was it was missing bad which sends too much air into the exhaust which sets the codes. Replacing the spark plugs and 2 wires cured it. Without monitoring the O2 operation with a scan tool it's hard to tell if the sensor is working properly or not. Seeing that it's just one sensor that's showing a problem you could just have a bad sensor.....unless the engine has a miss or a vacuum leak or something like that on the 1 bank.
Yes bank 1 is the passenger's side. The side of the engine with #1 cylinder is bank 1.
With your mileage I think I'd start by installing a new set of Motorcraft plugs, replacing the fuel filter, unless it's been done recently, cleaning the MAF again then clear the codes and see what happens.
Hi wheezer99 and welcome to FTE
I had an Expedition today with a similar problem other than I had a code for both banks lean. The problem with this one was it was missing bad which sends too much air into the exhaust which sets the codes. Replacing the spark plugs and 2 wires cured it. Without monitoring the O2 operation with a scan tool it's hard to tell if the sensor is working properly or not. Seeing that it's just one sensor that's showing a problem you could just have a bad sensor.....unless the engine has a miss or a vacuum leak or something like that on the 1 bank.
Yes bank 1 is the passenger's side. The side of the engine with #1 cylinder is bank 1.
With your mileage I think I'd start by installing a new set of Motorcraft plugs, replacing the fuel filter, unless it's been done recently, cleaning the MAF again then clear the codes and see what happens.
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