Surges at Steady Speed

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

POSSIBLE CAUSE ACTION

Insufficient fuel supply ^ Check fuel supply.

Faulty fuel pressure regulator ^ Check fuel pressure. Refer to DIAGNOSTIC CHARTS/FUEL SYSTEM PRESSURE TEST (CHART A-6).

Contaminated fuel ^ Check for water or excessive alcohol in fuel. Refer to ALCOHOL-IN-FUEL TEST.
^ Drain fuel tank and add clean fuel. Refer MAINTENANCE PROCEDURES/FUEL TANK DRAINING.

Dirty fuel filter ^ Replace fuel filter.

Lean operating condition ^ Check computer controls.
refer to COMPUTERIZED ENGINE CONTROLS/DIAGNOSIS AND TESTING PROCEDURES/DIAGNOSTIC CHARTS.

Vacuum leak ^ Inspect vacuum hoses for proper routing and damaged lines.
^ Check intake manifold, throttle body base and gasket.