Long-term fuel trim on Bank 1 indicates an over-rich mixture; the DME is removing fuel to compensate.
SYMPTOMS
- Check-engine light
- Rough idle
- Fuel smell
- Fouled plugs
- Worse economy
LIKELY CAUSES
- Leaking injector
- High fuel pressure
- Faulty MAF
- Contaminated O2 sensor
- Restricted air filter
DIAGNOSIS STEPS
- Read fuel trims
- Check fuel pressure
- Inspect injectors for leakage
- Check MAF and O2 data
RELATED PARTS
- Fuel injectors
- MAF sensor
- O2 sensors