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P0171 Diagnostic Trouble Code Discussion for February 2010

Fuel System Lean (Bank 1)


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Trouble Ticket Help Requests for DTC P0171
Help Request Posted
2005 Ford Escape Limited 3.0L MIL Lamp on VIN: 1FMCU04115
P0171: Fuel System Too Lean (Bank 1). ... has been replaced possibly with a used engine but this vehicle is very clean. Check engine light comes on and sets lean codes p0171 and p0174. Vehicle runs smooth and no idle issues but the long term fuel trims will both...
February 03, 2010
1999 Toyota RAV4 2.0L Excessive Emissions, Poor Idle Quality, Hesitation, Poor Fuel Economy, MIL Lamp on VIN: JT3GP10V2X
P0171: Fuel System Too Lean (Bank 1). ... come on intermittently at first with loss of power and rough idle. Searched TSB's. Found bulletin# EG012-01 for code P1133. Installed updated Toyota Air/Fuel ratio sensor,(new plugs, fuel filter,& air filter couple of weeks earlier). All was well for a...
February 03, 2010
2007 Ford F-150 XLT 5.4L MIL Lamp on VIN: 1FTXS21547
P0171: Bank 1 lean. This vehicle presented with a list of codes. #6 coil was replaced to correct the misfire. Attempted to unstick the solenoid for b2 cam by pulsing a ground to it with no luck. I removed the valve cover and found thick heavy sludge. I removed the sludge as well ...
February 04, 2010
2000 Subaru Outback 2.5L Hesitation, Stall VIN: 453BH6750Y
P0171: lean b1s1. Car came in for hard to start, hesitation, sags, stalls. Replaces Air Fuel Sensor, had code PO171. When hot its hard to start, you can put your foot to the floor and it wont rev up, but if you feather the throttle it will rev up fine. Test drive and try to pul...
February 04, 2010
2000 Jeep Grand Cherokee Limited 4.7L Misfire VIN: 1J4GW58N5Y
P0171: Fuel System Lean (Bank 1). Hi. This Jeep has me stumped. It came in missfiring and no power. Pulling off wires at coil over plugs, drives side makes little or no rpm drop. pass. side 2,4,6,8 large rpm drop. I have current ramped all coils and injectors, all look ok. fuel trims +25. tps ...
February 08, 2010
2004 Chevrolet Silverado 1500 5.3L MIL Lamp on VIN: 2GCEC19TX2
P0171: Fuel Trim System Lean (Bank 1). ... next day light on and code p0420 is on. I drove it for about 20 minutes and rechecked and found p0430 in code. this truck has a slight stumble at idle so I think it is the maf sensor. Back pressure test normal on cats did a crank test on the smog tester an...
February 10, 2010
2000 Toyota Avalon XLS 3.0L MIL Lamp on VIN: 4T1BF288GY
P0171: Fuel System Too Lean (Bank 1). Car came in with 3 Codes, the two listed above and a lean Bank #1. Looked in the archives and after cleaning the wires on the MAF the lean code was gone, but the Knock Sensor codes remain. Something odd was that while I was trying to fix the Lean Bank #1 code ...
February 11, 2010
2000 Ford F-150 XL 4.2L Poor Idle Quality, Misfire, MIL Lamp on VIN: IFTZF172XY
P0171: Lean bank 1. The scan tool will not show freeze frame info and in data stream I can see intermitant #3 injector fault(yes). All other are injector fault (no)
February 15, 2010
1999 Jeep Cherokee Limited 4.0L Poor Fuel Economy, MIL Lamp on VIN: 1J4FF68S6X
P0171: Fuel System Lean (Bank 1). Came in for Codes P0171 System too lean, P0131 Upstream O2 Voltage too low, P0138 Downstream O2 too high. Replaced both sensors and has same problem. The rear O2 is working correctly, 5 volts KOEO and 1 Volt running. Open Loop CO is good 2-3 %. Closed Loop CO ...
February 16, 2010
2006 Chevrolet Trailblazer LT 4.2L MIL Lamp on
P0171: Fuel System Lean (Bank 1). ... and replaced faulty evap vent solenoid. customer returns with MIL on again. This time it has a p0171 system lean. Intake was removed and inspected for vac leaks and cracks(none found) and reinstalled with new gaskets. Throt...
February 17, 2010
1999 GMC K1500 Suburban 5.7L MIL Lamp on VIN: 1GKFK16ROX
P0171: Fuel Trim System Lean (Bank 1). hello all, have a real problem 5.7 here. i have read through all the postings, followed all tests and am still stumped. just did leaking lower intake gaskets on this one, on test drive found it to be very low on power. replaced plugged fuel filter and fuel pum...
February 18, 2010
2003 GMC Yukon Denali 6.0L Poor Idle Quality, Misfire, Poor Fuel Economy, MIL Lamp on VIN: 1GKEK63U43
P0171: Fuel Trim System Lean (Bank 1). this denali is killing us. after a simple tune up and mass air flow sensor replacment and replacing the intake manifold assembly (burned through from shorted knock sensor harnness) causing vacuum leak. we replaced both knock sensors amd harness from gm.we did ...
February 18, 2010
2004 GMC Sierra 1500 5.3L Misfire, MIL Lamp on VIN: 2GTEK13TX4
P0171: Fuel Trim System Lean (Bank 1). Any help would be apprieciated. This vehicle came in with a miss and lean code on bank one. I checked fuel press. 62 P.S.I. I also checked for vaccume leaks and found none. Checked TSB's And O2 sensor not cracked. Cyl. 1,3,5,7 misses inter with 1,5 missing all...
February 18, 2010
1999 Toyota RAV4 2.0L Excessive Emissions, Poor Idle Quality, Hesitation, Poor Fuel Economy, MIL Lamp on VIN: JT3GP10V2X
P0171: Fuel System Too Lean (Bank 1). ... come on intermittently at first with loss of power and rough idle. Searched TSB's. Found bulletin# EG012-01 for code P1133. Installed updated Toyota Air/Fuel ratio sensor,(new plugs, fuel filter,& air filter couple of weeks earlier). All was well for a...
February 19, 2010
2004 Buick LeSabre Limited 3.8L Surge, Cuts out, MIL Lamp on VIN: 1G4HP52K94
P0171: Fuel Trim System Lean. I met the owner of this vehicle this afternoon to diagnose a SES light being on. Checked and found a po171.Upon start-up the engine would sputter and clear up.I checked for misfire readings and did see different cylinders misfire and then return to normal. I e...
February 21, 2010
2006 GMC Savana 2500 4.8L MIL Lamp on VIN: 1GTHG39V86
P0171: Fuel Trim System Lean (Bank 1). ... When I got the vehicle it was hot so I did not duplicate the cold start complaint. Scanned van found P0171 and P0174, long term fuel trim stuck at positive 24% and short term moving around in the positive single digits. Smo...
February 22, 2010
2001 Volkswagen Golf GL 2.0L MIL Lamp on VIN: 9BWGS61J61
P0171: Lean. I put a MAF on this for a code p0171. The MAF was under reporting, would show about 2 grams/sec at idle and only about 50 grams/sec WOT in 2nd gear driving at 40 mph. Replaced MAF and readigns were alot better 3.25 grams/second at idle and over [...]/second 40...
February 22, 2010
2003 GMC Yukon Denali 6.0L Poor Idle Quality, Misfire, Poor Fuel Economy, MIL Lamp on VIN: 1GKEK63U43
P0171: Fuel Trim System Lean (Bank 1). this denali is killing us. after a simple tune up and mass air flow sensor replacment and replacing the intake manifold assembly (burned through from shorted knock sensor harnness) causing vacuum leak. we replaced both knock sensors amd harness from gm.we did ...
February 24, 2010
1997 Acura CL 2.2L Poor Idle Quality, MIL Lamp on VIN: 1NUYA1245V
P0171: Fuel System Too Lean (Bank 1). The Short Term Fuel Trims at idle goes from 0 up to 10, at light cruise it goes from 5-30, under load it's between 0-10. The long term slowly creeps whle driving at cruise. No vacuum leaks found (checked hot and cold multiple times) Identifix was contacted an...
February 25, 2010
2006 Ford Expedition XLS 5.4L Surge, Cuts out, Misfire, MIL Lamp on VIN: 1FMPU175X6
P0171: lean bank 1 under load. TEST DROVE, RESET P0305 QND P0171 ON HARD Accel. bucks. pops, skips on wide open throttle. #5 compression 125 psi running. Customer(used car dealer) wanted Ford dealer opinion, Ford reccomended all plugs and coils after diagnosis. We replaced all plugs with fo...
February 25, 2010
2006 Ford Expedition XLS 5.4L Surge, Cuts out, Misfire, MIL Lamp on VIN: 1FMPU175X6
P0171: lean bank 1 under load. TEST DROVE, RESET P0305 QND P0171 ON HARD Accel. bucks. pops, skips on wide open throttle. #5 compression 125 psi running. Customer(used car dealer) wanted Ford dealer opinion, Ford reccomended all plugs and coils after diagnosis. We replaced all plugs with fo...
February 26, 2010
2001 BMW 325i 2.5L Hesitation, Stall, Misfire VIN: WBAAN37401
P0171: sys lean b1. ... p0171 sys lean b1. Also p1345 p1343 p1342 which my scan had no definition. I found a vacum leak, crank breather hose at dipstick tube was broken, and replaced. Also replaced spark plugs...
February 27, 2010
1999 Chrysler 300M 3.5L No Start VIN: 2C3HE66GXX
P0171: Fuel System Lean (Bank 1). Hello to all the great technicians out there! Got this old Chrysler that I need some advice on, please. Please hear me out, as I have found the TSB & archives about the problem I am having on this car and have done all I could without alot of expense or &#...
February 27, 2010
2005 Ford Escape Limited 3.0L MIL Lamp on VIN: 1FMCU04115
P0171: Fuel System Too Lean (Bank 1). ... has been replaced possibly with a used engine but this vehicle is very clean. Check engine light comes on and sets lean codes p0171 and p0174. Vehicle runs smooth and no idle issues but the long term fuel trims will both...
February 03, 2010
1999 Toyota RAV4 2.0L Excessive Emissions, Poor Idle Quality, Hesitation, Poor Fuel Economy, MIL Lamp on VIN: JT3GP10V2X
P0171: Fuel System Too Lean (Bank 1). ... come on intermittently at first with loss of power and rough idle. Searched TSB’s. Found bulletin# EG012-01 for code P1133. Installed updated Toyota Air/Fuel ratio sensor,(new plugs, fuel filter,& air filter couple of weeks earlier). All was well for a...
February 03, 2010
2007 Ford F-150 XLT 5.4L MIL Lamp on VIN: 1FTXS21547
P0171: Bank 1 lean. This vehicle presented with a list of codes. #6 coil was replaced to correct the misfire. Attempted to unstick the solenoid for b2 cam by pulsing a ground to it with no luck. I removed the valve cover and found thick heavy sludge. I removed the sludge as well ...
February 04, 2010
2000 Subaru Outback 2.5L Hesitation, Stall VIN: 453BH6750Y
P0171: lean b1s1. Car came in for hard to start, hesitation, sags, stalls. Replaces Air Fuel Sensor, had code PO171. When hot its hard to start, you can put your foot to the floor and it wont rev up, but if you feather the throttle it will rev up fine. Test drive and try to pul...
February 04, 2010
2000 Jeep Grand Cherokee Limited 4.7L Misfire VIN: 1J4GW58N5Y
P0171: Fuel System Lean (Bank 1). Hi. This Jeep has me stumped. It came in missfiring and no power. Pulling off wires at coil over plugs, drives side makes little or no rpm drop. pass. side 2,4,6,8 large rpm drop. I have current ramped all coils and injectors, all look ok. fuel trims +25. tps ...
February 08, 2010
2004 Chevrolet Silverado 1500 5.3L MIL Lamp on VIN: 2GCEC19TX2
P0171: Fuel Trim System Lean (Bank 1). ... next day light on and code p0420 is on. I drove it for about 20 minutes and rechecked and found p0430 in code. this truck has a slight stumble at idle so I think it is the maf sensor. Back pressure test normal on cats did a crank test on the smog tester an...
February 10, 2010
2000 Toyota Avalon XLS 3.0L MIL Lamp on VIN: 4T1BF288GY
P0171: Fuel System Too Lean (Bank 1). Car came in with 3 Codes, the two listed above and a lean Bank #1. Looked in the archives and after cleaning the wires on the MAF the lean code was gone, but the Knock Sensor codes remain. Something odd was that while I was trying to fix the Lean Bank #1 code ...
February 11, 2010
2000 Ford F-150 XL 4.2L Poor Idle Quality, Misfire, MIL Lamp on VIN: IFTZF172XY
P0171: Lean bank 1. The scan tool will not show freeze frame info and in data stream I can see intermitant #3 injector fault(yes). All other are injector fault (no)
February 15, 2010
1999 Jeep Cherokee Limited 4.0L Poor Fuel Economy, MIL Lamp on VIN: 1J4FF68S6X
P0171: Fuel System Lean (Bank 1). Came in for Codes P0171 System too lean, P0131 Upstream O2 Voltage too low, P0138 Downstream O2 too high. Replaced both sensors and has same problem. The rear O2 is working correctly, 5 volts KOEO and 1 Volt running. Open Loop CO is good 2-3 %. Closed Loop CO ...
February 16, 2010
2006 Chevrolet Trailblazer LT 4.2L MIL Lamp on
P0171: Fuel System Lean (Bank 1). ... and replaced faulty evap vent solenoid. customer returns with MIL on again. This time it has a p0171 system lean. Intake was removed and inspected for vac leaks and cracks(none found) and reinstalled with new gaskets. Throt...
February 17, 2010
1999 GMC K1500 Suburban 5.7L MIL Lamp on VIN: 1GKFK16ROX
P0171: Fuel Trim System Lean (Bank 1). hello all, have a real problem 5.7 here. i have read through all the postings, followed all tests and am still stumped. just did leaking lower intake gaskets on this one, on test drive found it to be very low on power. replaced plugged fuel filter and fuel pum...
February 18, 2010
2003 GMC Yukon Denali 6.0L Poor Idle Quality, Misfire, Poor Fuel Economy, MIL Lamp on VIN: 1GKEK63U43
P0171: Fuel Trim System Lean (Bank 1). this denali is killing us. after a simple tune up and mass air flow sensor replacment and replacing the intake manifold assembly (burned through from shorted knock sensor harnness) causing vacuum leak. we replaced both knock sensors amd harness from gm.we did ...
February 18, 2010
2004 GMC Sierra 1500 5.3L Misfire, MIL Lamp on VIN: 2GTEK13TX4
P0171: Fuel Trim System Lean (Bank 1). Any help would be apprieciated. This vehicle came in with a miss and lean code on bank one. I checked fuel press. 62 P.S.I. I also checked for vaccume leaks and found none. Checked TSB's And O2 sensor not cracked. Cyl. 1,3,5,7 misses inter with 1,5 missing all...
February 18, 2010
1999 Toyota RAV4 2.0L Excessive Emissions, Poor Idle Quality, Hesitation, Poor Fuel Economy, MIL Lamp on VIN: JT3GP10V2X
P0171: Fuel System Too Lean (Bank 1). ... come on intermittently at first with loss of power and rough idle. Searched TSB’s. Found bulletin# EG012-01 for code P1133. Installed updated Toyota Air/Fuel ratio sensor,(new plugs, fuel filter,& air filter couple of weeks earlier). All was well for a...
February 19, 2010
2004 Buick LeSabre Limited 3.8L Surge, Cuts out, MIL Lamp on VIN: 1G4HP52K94
P0171: Fuel Trim System Lean. I met the owner of this vehicle this afternoon to diagnose a SES light being on. Checked and found a po171.Upon start-up the engine would sputter and clear up.I checked for misfire readings and did see different cylinders misfire and then return to normal. I e...
February 21, 2010
2006 GMC Savana 2500 4.8L MIL Lamp on VIN: 1GTHG39V86
P0171: Fuel Trim System Lean (Bank 1). ... When I got the vehicle it was hot so I did not duplicate the cold start complaint. Scanned van found P0171 and P0174, long term fuel trim stuck at positive 24% and short term moving around in the positive single digits. Smo...
February 22, 2010
2001 Volkswagen Golf GL 2.0L MIL Lamp on VIN: 9BWGS61J61
P0171: Lean. I put a MAF on this for a code p0171. The MAF was under reporting, would show about 2 grams/sec at idle and only about 50 grams/sec WOT in 2nd gear driving at 40 mph. Replaced MAF and readigns were alot better 3.25 grams/second at idle and over [...]/second 40...
February 22, 2010
2003 GMC Yukon Denali 6.0L Poor Idle Quality, Misfire, Poor Fuel Economy, MIL Lamp on VIN: 1GKEK63U43
P0171: Fuel Trim System Lean (Bank 1). this denali is killing us. after a simple tune up and mass air flow sensor replacment and replacing the intake manifold assembly (burned through from shorted knock sensor harnness) causing vacuum leak. we replaced both knock sensors amd harness from gm.we did ...
February 24, 2010
1997 Acura CL 2.2L Poor Idle Quality, MIL Lamp on VIN: 1NUYA1245V
P0171: Fuel System Too Lean (Bank 1). The Short Term Fuel Trims at idle goes from 0 up to 10, at light cruise it goes from 5-30, under load it's between 0-10. The long term slowly creeps whle driving at cruise. No vacuum leaks found (checked hot and cold multiple times) Identifix was contacted an...
February 25, 2010
2006 Ford Expedition XLS 5.4L Surge, Cuts out, Misfire, MIL Lamp on VIN: 1FMPU175X6
P0171: lean bank 1 under load. TEST DROVE, RESET P0305 QND P0171 ON HARD Accel. bucks. pops, skips on wide open throttle. #5 compression 125 psi running. Customer(used car dealer) wanted Ford dealer opinion, Ford reccomended all plugs and coils after diagnosis. We replaced all plugs with fo...
February 25, 2010
2006 Ford Expedition XLS 5.4L Surge, Cuts out, Misfire, MIL Lamp on VIN: 1FMPU175X6
P0171: lean bank 1 under load. TEST DROVE, RESET P0305 QND P0171 ON HARD Accel. bucks. pops, skips on wide open throttle. #5 compression 125 psi running. Customer(used car dealer) wanted Ford dealer opinion, Ford reccomended all plugs and coils after diagnosis. We replaced all plugs with fo...
February 26, 2010
2001 BMW 325i 2.5L Hesitation, Stall, Misfire VIN: WBAAN37401
P0171: sys lean b1. ... p0171 sys lean b1. Also p1345 p1343 p1342 which my scan had no definition. I found a vacum leak, crank breather hose at dipstick tube was broken, and replaced. Also replaced spark plugs...
February 27, 2010
1999 Chrysler 300M 3.5L No Start VIN: 2C3HE66GXX
P0171: Fuel System Lean (Bank 1). Hello to all the great technicians out there! Got this old Chrysler that I need some advice on, please. Please hear me out, as I have found the TSB & archives about the problem I am having on this car and have done all I could without alot of expense or &#...
February 27, 2010