Hesitates or Stalls on Acceleration

Symptom: Engine hesitates or stumbles on acceleration, sometimes stalling. This condition can occur at any speed, but primarily from a stop. Vehicle may also experience a surge or rise and fall of engine speed at cruise or steady throttle.

POSSIBLE CAUSE ACTION


Electrical misfires ^ Check ignition system.
SEE IGNITION SYSTEM/ OSCILLOSCOPE PATTERNS.


Initial timing incorrect ^ Check base timing.
SEE IGNITION SYSTEM/ ADJUSTMENT PROCEDURES.


Incorrect Spark Advance ^ Check Spark Controls.
SEE IGNITION SYSTEM/ TIMING SPECIFICATIONS


Incorrect Air-Fuel mixture ^ Check fuel pressure.
^ Check O2 sensor.

^ Perform injector balance test (SFI only).


EGR malfunction ^ Check EGR system.


Faulty EVAP Canister purge ^ Check Fuel Evaporative System.


Restricted exhaust system ^ Check Catalytic Converter.


Dirty air filters ^ Clean or replace


Poor or contaminated fuel ^ Recommend higher grade fuel