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

Incorrect fuel pressure ^ Check fuel pump, filter and pressure regulator.

Contaminated fuel ^ Check for water or excessive alcohol in fuel. Alcohol/Contaminants-In-Fuel Testing Procedure
^ Drain fuel tank and add clean fuel.

Lean operating condition ^ Check computer controls
refer to COMPUTERS AND CONTROL SYSTEMS/ DIAGNOSIS, TESTING AND INSPECTION PROCEDURES.

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