GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2004 🢒 VUE - FWD 🢒 Engine 🢒 Engine Controls - 3.5L (L66) 🢒 Hesitation, Sag, Stumble

Hesitation, Sag, Stumble

Checks

Action

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 severe enough.

Preliminary Check
    • Refer to Symptoms - Engine Controls .

Fuel System Checks
    • Check for a restricted fuel filter or incorrect fuel pressure. Refer to Fuel System Diagnosis .
    • Check the fuel injectors. Perform the following procedures:
      • The Fuel Injector Coil Test Procedure--Refer to Fuel Injector Solenoid Coil Test .
      • The Fuel Injector Balance Test Procedure--Refer to Fuel Injector Balance Test with Tech 2 .
    • Check for water contamination of the fuel.
    • Check the evaporative emission (EVAP) control system for a saturated EVAP canister.

Ignition System Checks

Inspect the spark plugs for correct operation and good ignition system performance. Refer to Spark Plug Inspection .

Additional Checks
    • Check the Service Bulletins for any updates.
    • Check the generator output voltage.