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P0171 Diagnostic Trouble Code Discussion for October 2008

Fuel System Lean (Bank 1) *

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Trouble Ticket Help Requests for DTC P0171

	Help Request	Posted
	1996 Chevrolet C1500 Suburban 5.7L MIL Lamp on VIN: 3GNEC16R8T P0171: Fuel Trim System Lean (Bank 1). ... regulator changed with a P0171 code. Found vacumm leaks at MAP seal and brake booster outlet from manifold. Repaired both, cleared codes and reset trim. After 2 drive cycles P0171 reset. Bank 1 LT trim at 14%, ST at 13% and bank 2 LT at 13%, ST at 6% when ...	October 01, 2008
	2000 Ford F-150 XL 4.2L Poor Idle Quality, Hesitation, Misfire, MIL Lamp on VIN: 1FTZF1720Y P0171: System too lean Bank 1. As Above. Problem still exists,seems to smooth out above 3000rpm and misses bad below it.Check Engine light not re-flagging att.Any help appreciated guys.This is a good commertial account I don,t wany too lose. Thanks	October 01, 2008
	2005 Mazda 3 S 2.3L Poor Idle Quality, MIL Lamp on VIN: JM1BK32325 P0171: Adaptive Fuel Trim Too Lean (Bank 1). You know life's interesting when you need to ask for help twice in 1 week! Well here goes... This Mazda came in with CEL on & codes po171(system lean)& po 455(gross evap leak) fuel trim #s were +30 lft & sft @ idle & +5-10 or so anything above ...	October 01, 2008
	1997 Ford Expedition XLT 4.6L MIL Lamp on VIN: 1FMRU1761W P0171: fuel system lean bank 1. ... one. came in a week ago with both dtc's p0171 & po174. maf hertz was only 133 - should be 153 - 159 for our location. replaced the maf sensor. vehicle returned today with same trouble codes. maf hertz back to 138. sm...	October 02, 2008
	2002 Jeep Liberty Sport 3.7L MIL Lamp on VIN: IJ46L48K02 P0171: Fuel System Lean (Bank 1). ... lean, p0174 bank 2 lean, p0442 small evap leak, and p0455 large evap leak, we repaired the evap leaks( 2 broken lines) we smoked the intake for posable leaks none found, o2 readings look good LT fuel trims are both at +32 map coolent temp and all other rea...	October 02, 2008
	2003 Kia Spectra 1.8L Poor Fuel Economy, MIL Lamp on VIN: KNAFB12143 P0171: Fuel System Too Lean (Bank 1). ... detection pump. p0171 want to know which is the best symptom to change that part. p0441 and p0442 both evap problems. i smoked the evap system no leaks and drove the car the vehicle drives find.	October 02, 2008
	1997 Ford Expedition Eddie Bauer 5.4L MIL Lamp on VIN: 1FMFU18L2V P0171: lean bank 1. the codes will set on a short test drive. idles perfect.	October 09, 2008
	2001 Nissan Pathfinder LE 3.5L MIL Lamp on VIN: JN8DR07Y41 P0171: Fuel Trim Lean (Bank 1). clients concern is check engine light always on, test drove, vehicle runs good -tested and found that the long term fuel trim is high on both banks +30% -smoke tested for vacuum leaks, none found -tested for voltage drop from b- to engine with all loads on, .2...	October 10, 2008
	2002 Subaru Impreza WRX 2.0L MIL Lamp on VIN: JF1GG29632 P0171: Fuel System Too Lean (Bank 1). Came in for MIL. PO171, bank one lean. Smoke checked intake system, no leaks. Cleaned injectors on a double length injection flush. Cleared codes, sent customer away. Light came back in a week. Changed the front a/f ratio sensor with a genuine subaru sensor. C...	October 10, 2008
	2003 Ford Windstar SE 3.8L MIL Lamp on VIN: 2FMZA52493 P0171: Lean condition H2O11. Hi Guys, Looking for some help for this one, Have MIL light on with a PO171 and PO174 (lean condition bank 1 and 2) at first the O2 readings on both upstream sensors were around 80mv. I forced a rich condition and the sensors responded by going to 850mv. the v...	October 12, 2008
	2000 Ford Focus SE 2.0L Poor Idle Quality, Surge VIN: 1FAFP34P7Y P0171: bank 1 system lean. Vehicle was brought with idle problem. Will initally idle ok and then starts to idle rough and will eventually stall. Fuel pressure is 45psi - 52 psi. At idle short term fuel trim bank 1 is 42% if you bring off idle and up to about 2500 rpm, fuel trim goes to ...	October 13, 2008
	2001 Nissan Pathfinder LE 3.5L MIL Lamp on VIN: JN8DR07Y41 P0171: Fuel Trim Lean (Bank 1). clients concern is check engine light always on, test drove, vehicle runs good -tested and found that the long term fuel trim is high on both banks +30% -smoke tested for vacuum leaks, none found -tested for voltage drop from b- to engine with all loads on, .2...	October 13, 2008
	2003 Cadillac DeVille 4.6L Poor Idle Quality, Stall, Misfire VIN: 1G6KD54Y83 P0171: Fuel Trim System Lean (Bank 1). G.M. Techs your knowledge is needed.I have lost my --- on this one. Did have a bad vaccum leak,quick bucks, yea right 5 days later,1-3-5-7 missing randomly,compression chk. all above 140. Found T.S.B. on reprogram called dealer been done, hoping to pawn it on ...	October 15, 2008
	2000 Lincoln Navigator 5.4L Poor Idle Quality, MIL Lamp on VIN: 5LMPU28A2Y P0171: lean bank 1. THIS TRUCK KEEPS SETTING CODE p0174 p0171. MASS AIR FLOW SENSOR HAS BEEN REPLACED WITH KNOW GOOD ONE. YOU CAN DRIVE THIS TRUCK ON THE HIGHWAY FOR 2 HOURS AND NOT SET THIS CODE. DRIVE IT AROUND TOWN AND IT SETS 174 171 LEAN BANK 1 AND 2. THE INTAKE MANIFOLD WAS...	October 15, 2008
	2000 Toyota Corolla VE 1.8L MIL Lamp on VIN: 1NXBR12E1Y P0171: Fuel System Too Lean (Bank 1). ... service which is fluid changes. customer left and the next week called said the check engine light was on. we check for codes code p0171 system lean bank 1. check for vacuum leaks thinking we might of knocked off a vacuum line none found. smoke check vehic...	October 17, 2008
	1999 Ford Mustang GT 4.6L Cuts out, Stall, MIL Lamp on VIN: 1FAFP42X5X P0171: Bank 1 system too lean. ... intermittant lack of power and stalling at stops. About 6 months ago the car was towed for a no start. Car started for me with no symtoms. Scan test showed lean running codes. I replaced a (80%) plugged fuel filter and cleared codes. Car is now back with P...	October 20, 2008
	2003 Cadillac DeVille 4.6L Poor Idle Quality, Stall, Misfire VIN: 1G6KD54Y83 P0171: Fuel Trim System Lean (Bank 1). G.M. Techs your knowledge is needed.I have lost my --- on this one. Did have a bad vaccum leak,quick bucks, yea right 5 days later,1-3-5-7 missing randomly,compression chk. all above 140. Found T.S.B. on reprogram called dealer been done, hoping to pawn it on ...	October 21, 2008
	1999 Ford E-150 Econoline 4.2L Excessive Emissions, Poor Fuel Economy, MIL Lamp on VIN: 1FTRE1420X P0171: system lean b1. came in with P0171 and p0174 cleaned fuel injectors and intake,was very dirty.checked fuel pressure and smoke tested. Found small leaks from intake shafts and dissmissed as too small.watched scan data O2 sensors switching in sync Tps flawless MAF I thought a l...	October 22, 2008
	2002 Ford Windstar LX 3.8L Poor Idle Quality, Cuts out, Stall, Misfire VIN: 2FMZA55432 Checking cam signal, lots of noise and hash on wave form. If you unplug IAC valve cam signal goes clean and vehicle runs great other than no idle control with IAC unplugged. If you clear codes with IAC unplugged you have that obvious code and can run car at 15...	October 22, 2008
	2002 Ford Windstar LX 3.8L Poor Idle Quality, Cuts out, Stall, Misfire VIN: 2FMZA55432 Checking cam signal, lots of noise and hash on wave form. If you unplug IAC valve cam signal goes clean and vehicle runs great other than no idle control with IAC unplugged. If you clear codes with IAC unplugged you have that obvious code and can run car at 15...	October 23, 2008
	2002 Ford E-250 Econoline 5.4L Misfire, MIL Lamp on, NO POWER CAT CLEAN VIN: 1FTNE24L62 P0171: lean b1. problem was light to med. missfires on acelaration.with codes.plugs, and related coils were replaced. fuel filter was plugged. after repair due to time, found fuel press.not per. spec.and not holding.press.is going too high[over55-70plus]. have done press. reg...	October 27, 2008
	2000 Ford Focus SE 2.0L MIL Lamp on VIN: 1FAFP34P3Y P0171: system too lean. ... the functinal test due to mil on with the p0171 code present. The emissions are perfect. we are in a basic area so we don't have to check for N0x. we just check the egr functional. at the beginning I thought it was a vaccum leak or maf sensor contaminated ...	October 28, 2008
	1995 Ford F-150 Special 4.9L Stall, MIL Lamp on VIN: Y4TLA88515 P0171: bank 1 lean exhust. ... keep cutting key on off it starts up ,then stalls,the more you do this the better it gets after about 10 starts it runs fine all day cranks good starts every time.after 5 minutes of driving codes p0171,p0174,come on bank1, b...	October 29, 2008
	1999 Pontiac Bonneville SE 3.8L MIL Lamp on VIN: 1G2HX52K1X P0171: Fuel System Lean. hello, we have this bonneville w/ po171,lean condition. we replaced both o2 sensors,fuel pump&filter,m.a.p sensor,m.a.f. sensor, and can't find any vacuume leaks, exhaust is also new. doe's anyone have any other suggestions. i was laening toward a pressure...	October 29, 2008
	2001 Land Rover Discovery Series II SE 4.0L MIL Lamp on VIN: SALTW12451 P0171: bank 1 lean. Car came in for state inspection . Failed due to codes in memory. Checked for vacuum leaks,smoke tested manifold, looks good. Also checked MAF for readings ,seem to be with in range. there are no noticeable performance problems. the problem on this vehicle is ...	October 30, 2008
	2000 Ford Expedition XLT 5.4L Poor Idle Quality, MIL Lamp on VIN: 1FMPU18C5Y Hello, this vehicle runs extrely poor at idle when cold. I have Searhed for vac leaks with propane and come up with nothing. As soon as it is warm runs like a champ. Idle is good and performance is good. When cold it tries to idle up, and the LT trims stay at ...	October 31, 2008
	2006 Ford Crown Victoria Police Interceptor 4.6L MIL Lamp on VIN: 2FAFP71W26 P0171: bank 1 lean. ... from our local station. car came in with p0171 and p0174, not uncommon for us to see this. check fuel trims st was +5 - +10 and lt was +39 both banks. i sprayed for vacumm leaks found that intake like normal leaking, so we...	October 31, 2008