What this code means

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

1. Test fuel pressure at idle and under load
2. Replace fuel filter
3. Inspect fuel injectors
4. Check for vacuum leaks
5. Clean or test MAF sensor
6. 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.

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