System Too Rich at Idle (Bank 1)
Fuel trim on bank 1 hits the rich limit only at idle. Often a leaking injector dribbling fuel at low load, a sticky purge valve dumping fuel vapour, or fuel pressure regulator that fails to relieve pressure when intake vacuum is high.
Affected components
- Fuel injector
- Evap purge valve
- Fuel pressure regulator
Common causes
- High likelihood: Leaking injector at idle
- Medium likelihood: Purge valve stuck open
Possible symptoms
- Check engine light on
- Increased fuel consumption
- Black smoke from exhaust on acceleration
- Smell of unburned fuel, fouled spark plugs
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
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.