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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2006 🢒 Vibe - FWD 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 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.

Preliminary Check
    • Refer to Diagnostic System Check - Vehicle .
    • Refer to Symptoms - Engine Controls .

Sensor Checks
    • Inspect for a skewed engine coolant temperature (ECT) sensor.Use a scan tool to compare the engine coolant temperature with the ambient air temperature on a cold engine. If the coolant temperature reading is more than 5°C (9°F) more or less than the ambient air temperature on a cold engine, check for a high resistance in the coolant sensor circuit or in the sensor. Refer to Temperature Versus Resistance .
    • Check the accelerator pedal position (APP) sensor. A faulty APP sensor can cause a sluggish throttle response. First observe the APP sensor 1 voltage with the scan tool. The indicated voltage should be approximately 0.5-1.1 volts with the throttle closed. Next check the APP sensor 2 voltage with the scan tool. The indicated voltage should be approximately 1.2-2.0 volts with the throttle closed.
    • Check the throttle position (TP) sensor for binding or sticking. The voltage should increase at a steady rate as the throttle moves toward wide open throttle (WOT).
    • Inspect the operation of the mass air flow (MAF) sensor. Run the engine to normal operating temperature. Turn OFF all accessories and observe the MAF sensor at idle with a scan tool. If the MAF sensor reading is more than 3.5 g/s refer to DTC P0101 .

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 Balance Test Procedure--Refer to Fuel Injector Balance Test with Special Tool .
    • Check for water contamination of the fuel.
    • Check the evaporative emission (EVAP) control system. Refer to Evaporative Emission Control System Diagnosis .

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.