The Mass Air Flow (MAF) sensor measures how much air enters the engine.
Your ECU uses this airflow number to calculate:
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how much fuel to inject
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ignition timing adjustments
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idle stability
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emissions control strategy
When the MAF reading is wrong (dirty sensor, air leaks, wiring issues), the ECU “guesses” fuel delivery — and that’s when you get rough idle, hesitation, poor MPG, and the Check Engine Light.


