GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2006 🢒 DTS 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Surges/Chuggles

Inspection/Test

Action

DEFINITION: Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and slows down with no change in the accelerator pedal.

Preliminary

Be sure that the driver understands the transmission torque converter clutch (TCC), and A/C compressor operation as explained in the owners manual. Inform the customer how the TCC and the A/C system operate.

Sensor/System
    • Inspect for contaminated heated oxygen sensors (HO2S).
    • Inspect the mass air flow (MAF) sensor for proper installation, obstruction, contamination, and damage. Refer to Manifold Absolute Pressure Sensor Replacement .
    • Inspect the manifold absolute pressure (MAP) sensor for proper installation, obstruction, contamination, and damage. Refer to Manifold Absolute Pressure Sensor Replacement .
    • Inspect the MAF and MAP sensors for proper seating of the connectors and terminals.
    • Ensure the quality of the MAP sensor vacuum source.
    • Inspect the exhaust gas recirculation (EGR) system for proper operation. Refer to Exhaust Gas Recirculation (EGR) System Description .
    • Monitor the knock sensor (KS) system for excessive spark retard activity. Refer to the knock sensor description within the Electronic Ignition (EI) System Description .

Fuel System
    •  Test the fuel system for correct operation, restriction, volume, and pressure. Refer to Fuel System Diagnosis .
    • Test for proper operation of the fuel injectors. Refer to Fuel Injector Diagnosis .
    • Test for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Inspect the throttle body for coking. Refer to Throttle Body Inspection and Cleaning .
    • Inspect for lean or rich conditions. Refer to DTC P0171, P0172, P0174 or P0175 Conditions for Running the DTC. Refer to DTC P0171 or P0172 or DTC P0174 or P0175 .

Ignition System
    • Inspect for proper ignition system operation. Refer to Electronic Ignition (EI) System Diagnosis .
    • Inspect the spark plugs. Refer to Spark Plug Inspection .
    • Inspect the spark plugs for correct application. Refer to Ignition System Specifications .
    • Inspect for damaged ignition coils within the ignition coil module assemblies.
    • Inspect for damaged or misaligned spark plug boots.
    • Inspect the crankshaft position (CKP) sensor for damage and proper installation. Refer to Crankshaft Position Sensor Replacement .
    • Inspect the CKP sensor and harness for electromagnetic interference (EMI).

Additional Inspections
    • Inspect the vacuum hoses for splits, kinks, and improper connections or routing.
    • Inspect the engine electrical system for correct operation. Refer to Charging System Test .
    • Inspect TCC operation. Refer to Torque Converter Diagnosis .
    • Inspect for a restrictive exhaust system. Refer to Restricted Exhaust .