P2191 — System Too Lean at Higher Load (Bank 1)
Bank 1 fuel trim hits the lean limit only at higher engine load. Pattern points to a fuel-supply restriction — failing fuel pump, blocked filter, or weak injectors — rather than a vacuum leak (which would dominate at idle).
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Fuel pump
- Fuel filter
- Fuel injector
- Mass air flow sensor
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Fuel pump weak under load
- Fuel filter clogged
- MAF reads low at high airflow
Possible symptoms
- Check engine light on
- Rough idle, possible stalling
- Hesitation or hard cold start
- Power loss under load
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.