Step 12 - A rare occurrence, but it does happen, if everything has not helped an engine hesitation and low power and the ignition system is suspect, remove the harmonic balancer to inspect the woodruff key. This key can become worn allowing the ignition trigger to become retarded causing the engine hesitation.

Helpful Information

Hesitation Definition - An engine hesitation is an interruption of continuous power during acceleration. When a engine is hesitating it will cause the car to lunge or surge which will cause a sudden jerk as the car slows down. This condition can cause dangerous situations in heavy traffic when drivers behind expect continuous forward movement.


Older engine's are equipped with a distributor ignition system. This systems can cause hesitation when maladjusted, by using a timing light this situation can be checked and corrected. If the timing is adjusted too far retarded (behind the timing mark) in relationship to the engine crankshaft it will cause hesitation. If the engine timing is way off (20 degrees or more) check the timing belt or timing chain, the crankshaft/camshaft correlation.


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)