| Description |
Potential Problem |
| Sweet odor, usually accompanied by steam from under the hood |
Antifreeze or coolant leak |
| Heavy, thick odor, possibly accompanied by smoke from under the hood or
from the exhaust |
Burning oil |
| Acrid odor, like burned toast |
Electrical short |
| Continuous, heavy sulfur odor, like rotten eggs |
Emissions |
| Burning material or rubber odor |
Overheated brakes or clutch |
| Metallic odor, usually accompanied by antifreeze/coolant odor |
Overheating |
| Performance Problem |
How to Describe It |
| Cuts out |
Temporary, complete loss of power. Engine quits at sharp, irregular
intervals. May occur repeatedly or intermittently. Usually worse under heavy acceleration. |
| Detonation |
Mild to severe ping, usually worse under acceleration and load. Engine
makes sharp, metallic knocks that change with throttle opening. 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 pressed. Can occur at all
speeds. Usually most severe when starting from a stop. May cause engine to stall. |
| Missing |
Pulsation or jerking that changes with engine speed. Exhaust has a
steady spitting sound at idle or low speed. Not normally felt above 30 mph. |
| Rough idle |
Engine runs unevenly at idle. Car may also shake. |
| Sluggish |
Engine delivers limited power under load or at high speed. Won’t
accelerate as fast as normal. Loses too much speed going up hills. Has less speed than
normal. |
| Spongy |
Less than anticipated response to increased throttle opening. Little
or no increase in speed when accelerator is pushed down to increase cruising speed.
Continuing to push pedal down will finally give an increase in speed. |
| Stall |
Engine stops running or dies out. May occur at idle or while driving. |
| Surge |
Vehicle speeds up and slows down with no change on accelerator pedal.
Can occur at any speed. |
