Step 6 - The air intake to the engine is metered by a mass air flow sensor, this sensor provides feedback data to the computer which is then proccessed. If this intake system is allowed to leak it will cause a misreading making the engine hesitate. Inspect the intake boot for tears or holes and replace if needed.

Replacement Air Intake Boot

Step 7 - The mass air flow sensor is used to measure the air that travels into the engine. Inside this sensor is a hot wire that becomes contaminated which inhibits its ability to provide correct information to the computer. If this sensor has more than 70,000 miles servicing the sensor can help cure engine hesitation.

Service Mass Air Flow Sensor

Step 8 - The throttle bore is designed to control the volume of air the engine will ingest. The butterfly and throat of the bore (plate) becomes contaminated with impurities and must be cleaned much like the mass air flow sensor. Once this condition is corrected the engine can return to normal operation.

Throttle Body Service

Step 9 - The spark plugs of an engine are designed to ignite the fuel air mixture inside the combustion chamber to provide the engine's power. If these spark plugs or maladjusted or worn they can cause the ignition timing to change causing a hesitation, remove the spark plugs to inspect.

Spark Plug

Step 10 - The clutch is designed to release the engine from the transmission, when this part wears it can cause a hesitation in the motion of the car. To test this condition drive the car at a steady speed, then very lightly tap the clutch pedal, if the car responds the clutch is worn.

Step 11 - A timing belt or chain is used to keep the engine crankshaft to camshaft relationship correct. If this timing becomes misaligned, the engine can experience low power and hesitation.


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2015-01-09)