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 capacity Check fuel capacity,

Faulty fuel pressure regulator Check fuel pressure,

Contaminated fuel Check for water or excessive alcohol in fuel,
drain fuel tank and add clean fuel

Dirty fuel filter Replace fuel filter.

Lean operating condition Check computer controls,

Plugged fuel injector Perform injector service (cleaning),

Vacuum leak Inspect vacuum hoses for proper routing and damaged lines, check intake manifold/throttle body area