Car Trouble Symptom Description
Cuts out Temporary, complete loss of power. Engine quits at
Irregular intervals. May occur repeatedly or intermittently,
Usually under heavy acceleration.
Detonation Mild to severe pings, usually worse under acceleration.
Sounds like popcorn popping.
Dieseling Engine runs after ignition switch is turned off.
Runs unevenly and may make knocking noises.
Hesitation Momentary lack of response as accelerator is passed. Can occur
At any speed, usually most severe when starting from
complete stop. May cause engine to stall.
Miss Pulsation or jerking that changes with engine speed. Exhaust has
Steady spitting sound at idle or low speed.
Not normally felt above 30 mph.
Rough Idle Engine delivers limited power under load or at high speed.
Sluggish Doesn’t accelerate as fast as normal. Loses speed going uphill.
Vehicle has less speed than normal.
Spongy Little or no increase in speed when accelerator is pressed
Continuing to push pedal down will eventually increase speed.
Stall Engine stops running or dies. May occur at idle or while driving.
Surge Vehicle speeds up and slows down with no change to accelerator
pedal. Can occur at any speed.