Hesitation/Sag/Stumble

SYMPTOM DESCRIPTION:
Momentary lack of response when the accelerator is pushed down. Can occur at any speed. Usually most severe from a stop or initial take off. Engine may stall if condition is bad enough. Check the following systems and components.



COMPUTER INPUTS/OUTPUTS
^ THROTTLE POSITION SENSOR/SWITCH: Check adjustment. Refer to Throttle Position Sensor,
^ AIR FLOW METER: Check for sticking flap.
^ EFI CONTROL UNIT:
^ OXYGEN SENSOR: Damaged or defective oxygen sensor.



FUEL
^ FUEL PRESSURE: Check for insufficient fuel pressure or volume.
^ FUEL INJECTORS: Clogged or stuck injector, poor spray pattern.
^ WATER CONTAMINATED FUEL.




IGNITION
^ Faulty spark plug wires.
^ Fouled spark plugs.




EMISSIONS
^ EVAPORATIVE SYSTEM: Cannister purge system operation.




ENGINE
^ CHARGING VOLTAGE: Test battery condition and alternator output.