Engine Surges While Cruising

Perform switch monitor function test. See SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.
Verify Throttle Position (TP) sensor has correct adjustment and resistance value. See ADJUSTMENTS article in the ENGINE PERFORMANCE section.
Check oxygen sensor.
Check throttle linkage operation.
Check intake manifold vacuum. Vacuum should be more than 17.7 Hg at idle.
Check air filter element.
Check ignition timing.
Ensure fuel system pressure is correct.
Check for restricted exhaust system.