Lincoln navigator 98 I have a code p0171 bank1

P0171 Fuel Trim,Bank1 System too Lean, P3211 no such code!! nearest I could find is P0321 Ign./Distributor Eng.Speed Inp.Circ Range/Performance, 1st lesson never clear codes until you have found the fault!! are you using a cheap code reader or a garage one??

The lean code is making the computer dump fuel(black smoke). First check vacuum lines( on yours I would replace all them, it's 17 year old), Listen for any hissing noise. Being a 98, I'm not sure if you have a MAF sensor. But also make sure all the air filter hoses are connected and tightened down.

Definition of Diagnostic Trouble Code P1506 Audi: Closed Throttle Position Switch Does Not Open/Short to Ground BMW: Idle-Speed Control Valve Opening Solenoid Control Circuit Signal High Ford: Idle Air Control Overspeed Error (see P0507) Jaguar: Idle Air Control System RPM Lower Than Expected - B Bank Kia: IAC Valve Opening Coil Voltage High Lincoln: Idle Air Control Overspeed Error (see P0507) Mazda: Idle Air Control Overspeed Error Mercury: Idle Air Control Overspeed Error (see P0507) Porsche: Throttle Jacking Unit Lower Mechanical Stop, Signal Implausible Volkswagen: Closed Throttle Position Switch Does Not Open/Short to Ground Volvo: IAC Valve Opening Signal
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Definition of Diagnostic Trouble Code P1151 Audi: Bank1, Long Term Fuel Trim, Range 1 Leanness Lower Limit Exceeded BMW: Oxygen Sensor Heater Circuit Signal Intermittent (Bank 2 Sensor 1) Ford: Lack Of Heated Oxygen Sensor Bank 2 Sensor 1 Switches - Sensor Indicates Lean Jaguar: Lack of H02S-21 switch, sensor indicates lean Land Rover: Lambda control limit bank 2.Implausible signal/condition Lincoln: Lack Of Heated Oxygen Sensor Bank 2 Sensor 1 Switches - Sensor Indicates Lean Mazda: Lack Of Heated Oxygen Sensor Bank 2 Sensor 1 Switches - Sensor Indicates Lean Mercury: Lack Of Heated Oxygen Sensor Bank 2 Sensor 1 Switches - Sensor Indicates Lean Subaru: HO2S-12 Heater Circuit High Input Toyota: Coolant Path Clog Up for Coolant Heat Storage System Volkswagen: Bank1, Long Term Fuel Trim, Range 1 Leanness Lower Limit Exceeded
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Definition of Diagnostic Trouble Code P0302 Category: Powertrain Definition: Cylinder 2 Misfire DetectedNote: This definition of P0302 is applied to all manufacturers
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Definition of Diagnostic Trouble Code P0171 Category: Powertrain Definition: System Too Lean Bank 1Note: This definition of P0171 is applied to all manufacturers

• In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
• Inspect all vacuum and PCV hoses, replace if necessary

P1131 Lack of HO2S-11 Switch ,Sensor Lean
P1151-Lack of HO2S-21 Switch ,Sensor Lean
PO171- System to Lean (Bank 1)
PO174-Systen to Lean (Bank 2)

Fuel Filter -Plugged
Low Fuel Pressure
Evap System -Leaks
Leaks - in ducting,air filter to throttle
PCV -Leaks
Exhaust System -Leaks
O2 Sensors-worn out

Misfire on cylinder #4

The O2 Code is a result of the misfire
not a problem with sensor

www.engine-light-help.com/generic-check-engine-light-codes.html

P0171 - Fuel Trim, Bank1 System too Lean
VW DTC 16555 (P0171) - Fuel Trim, Bank1 System too Lean
By only pulling battery power from the ECU doesn't clear the codes on OBDII systems.
You must have access to a VAS, VAG-COM, Bosch KTS, ... diagnostic scantool. The ECU (Electronic Control Unit for engine management) is seeing a fuel trim that's much too lean even with the ECU making adjustments. Colud be the MAF (Mass Air Flow) sender out of order, the pre-cat O2 sensor, or a significant vacuum leak. You need to confirm / deny working parts with a 2nd gear pull data-logging measuring blocks 002, + 032 (VAS, VAG-COM).

i had the same trouble, there is a rubber boot under the cover on the top of the motor, it is coming from the egr valve, takes about 5 mins to repair and less than 5 dollars.

mass air flow sensor is not the problem, I had the exact same problem and have done much research on this. Check the PVC rubber hoses, especially the elbows for cracks. You probably noticed your gas mileage has been horrible too. Hope this helps

Here are the possible causes for a PO171:

• Base engine mechanical problem causing a lean A/F condition
• Check for air leaks in the Air Induction system (e.g., in the intake manifold)
• Check for air leaks in the exhaust manifold and in the exhaust pipes
• Check for air leaks in the PCV system and in its related hoses and/or valve
• Fuel control sensor is out of calibration (e.g., ECT, IAT or MAP)
• Fuel delivery component fault (clogged filter, low fuel pressure)
• HO2S has failed (it may be contaminated with fuel, silicone or water)
• Vacuum hose is disconnected, broken, leaking or loose

Please let me know if this information is helpful. Positive feedback is appreciated. Thank You!