Surges/Chuggles

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



PRELIMINARY CHECKS

^ Perform the careful visual checks as described in "Preliminary Checks."
^ Be sure driver understands transaxle torque converter clutch, and A/C compressor operation as explained in the owner's manual.

^ CHECK: For Service Bulletin updates.

SENSORS

^ CHECK: Oxygen Sensor (O2S). The O2S should respond rapidly to the varying quantities of oxygen in the exhaust system. After the O2S has reached operating temperature, the voltage should change quickly, and can go as high as 1 volt and as low as 0.1 volt in less than a second. If this response time is slow or voltage is at a steady level, the O2S should be checked for silicon, glycol or other contamination. The O2S may have a white powdery coating (silicon contamination) or a green coating (glycol contamination) that would result in a false signal voltage to PCM, and may lead to a driveability complaint.

IGNITION SYSTEM

^ CHECK: For proper ignition voltage output using spark tester (ST-125) J 26792 or equivalent.
^ CHECK: Spark plugs. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits. Spray spark plug cables with a mist of water and check for shorts. Repair or replace as necessary.

FUEL SYSTEM

NOTICE: To determine if the condition is caused by a rich or lean system, the vehicle should be driven at the speed of the complaint. Monitoring long term fuel trim will help identify a problem.

Lean - Long term fuel trim near 198. Refer to "Diagnostic Aids" of DTC 44 chart. Powertrain Controls - ECM/PCM
Rich - Long term fuel trim near 58. Refer to "Diagnostic Aids" of DTC 45 chart. Powertrain Controls - ECM/PCM

^ CHECK: Fuel pressure while condition exists. Use CHART A-7. Related Tests, Information and Procedures
^ CHECK: In-line fuel filter. Replace if dirty or plugged.
^ CHECK: For plugged injectors per injector balance test.
^ CHECK: For contaminated fuel.

ADDITIONAL CHECKS

^ CHECK: Vacuum lines for kinks or leaks.
^ CHECK: Generator output voltage. Repair if less than 9 or more than 16 volts.
^ CHECK: PCM grounds for being clean, tight and in their proper location.