Hesitation, Sag, Stumble

SYMPTOM DESCRIPTION
Engine power variation, under steady throttle or cruise. Feels like the vehicle speeds up and slows down, with no change in the accelerator pedal.




SYSTEM OR COMPONENT TO CHECK ACTION


FUEL NOTE To determine if the condition is caused
by a rich or lean system, the vehicle should be
driven at the speed of the complaint.
Monitoring block learn will help identify problem.
LEAN Block learn more than 150. Check for
DTC 44Powertrain Controls - ECM/PCM
RICH Block learn less than 115. Check for
DTC 45 Powertrain Controls - ECM/PCM
CHECK FUEL PRESSURE
Testing and Inspection
Restriction in in-line fuel filter.




IGNITION CHECK Secondary ignition voltage output with
spark tester J 26792 or equivalent (ST-125).
Spark plugs, wet plugs, cracks, wear, improper
gap, burned electrodes or heavy deposits.
Ignition timing.




EMISSIONS CHECK EGR system Testing and Inspection





ENGINE CHECK Vacuum lines for kinks and leaks.
Generator output voltage. Repair if less than
9 or more than 16 volts.
TCC operation.
NOTE Be sure driver understands
Torque Converter Clutch (TCC) and A/C
compressor operation in owner's manual.