Hesitation, Sag, Stumble

DEFINITION
Momentary lack of response as the accelerator is pushed down. Can occur at all car speeds. Usually most severe when first trying to make the vehicle move, as from a stop sign. May cause the engine to stall if severe enough.

PRELIMINARY CHECKS
^ Perform the careful "Visual And Physical Checks" in Preliminary Checks. - Important Preliminary Checks

FUEL SYSTEM
^ Check Throttle Position (TP) sensor for binding or sticking or misadjustment. Refer to Throttle Position Sensor / Adjustments. Adjustments
^ Check Mass Air Flow (MAF) sensor response and accuracy. Refer to Mass Air Flow Sensor / Testing and Inspection. Testing and Inspection

IGNITION SYSTEM
^ Check spark plug wires for being faulty.
^ Check spark plugs for being fouled.
^ Ignition system for moisture, dust, cracks, burns, etc.
^ Open ignition system ground.
^ Ignition timing. See underhood "Vehicle Emission Control Information label."

ADDITIONAL CHECKS
^ Check for correct ECM, see Technical Service Bulletins.
^ Check generator output voltage.
^ Check EGR valve operation, refer to Chart C-7A EGR System Check. Testing and Inspection