Surges and/or Chugs

Symptom: Engine power variation under steady throttle or cruise. Feels like the car speeds up and slows down with no change in the accelerator pedal.

NOTE: This symptom may be caused by an accumulation of intake valve deposits and/or clogged fuel injectors.

POSSIBLE CAUSES

Emission Control Systems

- Intermittent EGR at idle.

Ignition System

- Ignition timing. See Emission Control Information label.
- Faulty ignition system.

Fuel System

- Inline fuel filter dirty or restricted.
- Fuel pressure.
- Oxygen sensor operation.

Starting and Charging Systems

- Alternator output voltage.