Hesitation, Sag or Stumble

DEFINITION: The vehicle has a momentary lack of response when pushing down on the accelerator. The condition can occur at any vehicle speed. The condition is usually most severe when trying to make the vehicle move, as from a stop sign. The condition may cause the engine to stall if it is severe enough.

PRELIMINARY CHECKS
Refer to Important Preliminary Checks. Testing and Inspection

FUEL SYSTEM CHECKS

^ Check the fuel pressure. Refer to Fuel Supply System Check.
^ Check for water contamination in the fuel. Refer to Contamination Testing.
^ Perform the Injector Balance Test. Refer to Fuel Systems. Testing and Inspection

^ Check for low fuel pressure after a cold start or during moderate or full throttle acceleration. If fuel pressure drops below specification, there is possibly a faulty fuel pump or a restriction in the fuel system. Refer to Fuel Supply System Check.

ADDITIONAL CHECKS

^ Check the Service Bulletins for control module software updates.
^ Check the generator output voltage.