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Home >> Hummer >> 2009 >> H3 Base, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Engine Controls And Fuel - 5.3L - Introduction) >> Description and Operation >> Fuel System Description >> Fuel Metering Modes of Operation >> Deceleration Mode
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Deceleration Mode

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When the driver releases the accelerator pedal, air flow into the engine is reduced. The ECM monitors the corresponding changes in the TP, the MAP, and the MAF. The ECM shuts OFF fuel completely if the deceleration is very rapid, or for long periods, such as long, closed-throttle coast-down. The fuel shuts OFF in order to prevent damage to the catalytic converters.