Manifold Absolute Pressure / Mass Air Flow - Throttle Position Correlation at Idle
At idle, the relationship between MAP/MAF and throttle position does not match the calibrated map — typically a vacuum leak, dirty MAF, sticking throttle plate, or sensor drift.
Affected components
- Manifold absolute pressure sensor
- Mass air flow sensor
- Throttle position sensor
- Intake manifold
Common causes
- High likelihood: Vacuum leak — cracked hose, gasket, or PCV
- Medium likelihood: MAF sensor contaminated
- Medium likelihood: Carbon buildup at throttle plate
Possible symptoms
- Check engine light on
- Power loss, hesitation under acceleration
- Rough or unstable idle
- Increased fuel consumption
- Possible difficulty starting
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
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.