Fuel System Lean During Acceleration
2004-2007 Buick Rainier 4.2L I6 🇨🇦
Description
The PCM detected that during power enrichment mode (heavy acceleration in closed loop), the expected rich condition was not detected by the O2 sensors. This means the fuel system cannot supply adequate fuel during hard acceleration. A plugged fuel filter or restricted fuel line is a common cause.
Symptoms
- Check Engine Light
- Hesitation or stumble during hard acceleration
- Loss of power under load
- Poor fuel economy
- Engine misfires under load
Common Causes
- Clogged fuel filter
- Weak or failing fuel pump
- Restricted fuel line
- Faulty oxygen sensor
- Vacuum leak
- Contaminated or clogged fuel injectors
- Dirty MAF sensor
Diagnostic Steps
- Test fuel pressure at idle and under load
- Replace fuel filter
- Inspect fuel injectors
- Check for vacuum leaks
- Clean or test MAF sensor
- Monitor long-term fuel trim values
Repair Notes
Replace fuel filter and test fuel pump pressure/volume. If fuel delivery is adequate, check for vacuum leaks and dirty injectors.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1171 on Other Vehicles
Common Questions
What does code P1171 mean on a 2004-2007 Buick Rainier?
P1171 stands for "Fuel System Lean During Acceleration". The PCM detected that during power enrichment mode (heavy acceleration in closed loop), the expected rich condition was not detected by the O2 sensors. This means the fuel system cannot supply adequate fuel during hard acceleration. A plugged fuel filter or restricted fuel line is a common cause.
What are the symptoms of P1171 on a Buick Rainier?
Common symptoms of P1171 include: Check Engine Light, Hesitation or stumble during hard acceleration, Loss of power under load, Poor fuel economy, Engine misfires under load.
What causes P1171 on a 2004-2007 Buick Rainier?
Common causes of P1171 include: Clogged fuel filter, Weak or failing fuel pump, Restricted fuel line, Faulty oxygen sensor, Vacuum leak, Contaminated or clogged fuel injectors, Dirty MAF sensor.