GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1999 🢒 Intrigue 🢒 Engine 🢒 Engine Controls - 3.5L 🢒 Surges/Chuggles

Checks

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
    • Refer to Symptoms, Important Preliminary Checks Before Starting.
    • Search for bulletins.
    • Check the PCM grounds for being clean, tight and in their proper locations.
    • Be sure the driver understands transmission torque converter clutch, and A/C compressor operation as explained in the owners manual. Inform the customer how the TCC and the A/C clutch operate.

Sensor/System
    • Check Heated Oxygen Sensor (HO2S) #1. HO2S #1 should respond quickly to different throttle positions, if it does not, check the HO2S for the following conditions:
         -- Silicon or other contaminants from fuel, or use of improper RTV sealant.
         -- Phosphorus from excessive oil consumption.
        Either material may cover the sensor with a white powdery coating and result in a high but false signal voltage (rich exhaust indication). The PCM will then reduce the amount of fuel delivered to the engine causing a severe driveability problem.
    • Check the MAF sensor connections. Repair or replace terminals as necessary.
    • Check the EGR system for proper operation.

Fuel System
    • Check for low fuel pressure. Refer to Fuel System Pressure Test .
    • Check for a restricted fuel filter.
    • Check for contaminated fuel. Refer to Fuel Quality Diagnosis .
    • Check each injector harness is connected to the correct injector/cylinder according to the firing order. Relocate injector harnesses as necessary.
    • Check items which can cause an engine to run rich (long term fuel trim near -99%).
    • Check items that can cause an engine to run lean (long term fuel trim near 100%).

Ignition System

Remove spark plugs and check for the following:

    • Wet plugs
    • Cracks
    • Wear
    • Improper gap
    • Burned electrodes
    • Heavy deposits

An improper spark plug gap will cause a driveability problem. The spark plug gapping should be done using a wire gauge gap tool (J 41319). Refer to Spark Plug Replacement. If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

    • Check for loose ignition control module grounds.
    • Check the spark plugs for proper heat range.
    • Check for proper ignition voltage output with spark tester J 26792. Refer to Secondary Ignition Diagnosis .

Additional Checks
    • Visually / physically check: Vacuum hoses for splits, kinks, and proper connections and routing as shown on Vehicle Emission Control Information label.
    • Check TCC operation. Using a scan tool should indicate an RPM drop, when the TCC is commanded on. Refer to Flexplate/Torque Converter Vibration Test in Automatic Transmission -- 4T65-E.
    • Check the exhaust system for a possible restriction. Refer to Restricted Exhaust System Check .
    •  Check for improper harness routing. An engine miss condition can be caused by Electromagnetic Interference (EMI) on some engine controls circuits. Use the scan tool to check for erratic sensor values or excessive changes in indicated RPM with little change in actual engine RPM. This may indicate EMI is present. If a problem exists, check for improper routing of the harness near high voltage components (Ignition Components) or high current components (alternator, motors, solenoids etc.).
    •  Check the charging system. a bad diode in the alternator can allow AC noise to enter the electrical system. This may affect the engine controls system operation. Refer to Charging System Check .
    • Check the Trans Range switch circuit and be sure the scan tool indicates vehicle is in drive with gear selector in drive or overdrive.