Hesitation, Sag, Stumble

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Inspections	Action
DEFINITION: The vehicle has a momentary lack of response when depressing 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 the condition is severe enough.
Preliminary	Refer to Symptoms - Engine Controls .
Fuel System	Test the fuel pressure. Refer to Fuel System Diagnosis . Inspect the throttle position (TP) sensor for binding or sticking. Voltage should increase at a steady rate as the throttle moves toward wide open throttle (WOT). Test for water contamination in the fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Test the canister purge system for proper operation. Perform the fuel injector coil test. Refer to Fuel Injector Coil Test . Test for low fuel pressure after a cold start or during a moderate or full throttle acceleration.
Ignition System	Inspect for fouled spark plugs. Inspect for proper ignition system performance.
Additional	Search for Service Bulletins for calibration updates. Inspect for a restricted exhaust. Refer to Restricted Exhaust in Engine Exhaust.