GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 Safari - 2WD 🢒 Engine 🢒 Engine Electrical 🢒 Surges/Chuggles

Inspections

Action

DEFINITION: The engine has a power variation under a steady throttle or cruise. The vehicle feels as if it speeds up and slows down with no change in the accelerator pedal position.

Preliminary
    • Refer to Symptoms - Engine Controls .
    • Ensure that the driver understands the torque converter clutch operation.
    • Ensure that the driver understands the A/C compressor operation.
    • Use the scan tool to ensure that the reading of the vehicle speed sensor (VSS) matches the vehicle speedometer. This excludes vehicles with electronic transmissions where some variation between the VSS and the speedometer is normal.
    • Ensure that the transmission fluid is at the proper level.

Sensor

Display the scan tool parameters for the various engine controls sensors. Inspect for any abnormal readings.

Fuel System
    • Test the fuel pressure while the condition exists. Refer to Fuel System Diagnosis .
    • Inspect the in-line fuel filter for restrictions. Refer to Fuel System Diagnosis .

Ignition System
    • Inspect for the proper ignition output voltage using the J 26792 spark tester or the equivalent. Refer to Distributor Ignition (DI) System Diagnosis .
    • Inspect the secondary ignition system and spark plugs. Refer to Spark Plug Inspection .

Additional
    • Inspect the control module grounds for being clean, tight, and in their proper locations. Refer to Power and Grounding Component Views in Wiring Systems.
    • Inspect the generator output voltage. Refer to Charging System Test in Engine Electrical.
    • Inspect for an intermittent EGR problem.
    • Inspect for torque converter clutch (TCC) operation. Refer to Symptoms - Automatic Transmission in Automatic Transmission-4L60-E.
    • Inspect the exhaust system for a possible restriction. Refer to Restricted Exhaust in Engine Exhaust.