Surges/Chuggles

DEFINITION:
Engine power variation under steady throttle. Vehicle speeds up and slows down with no change to the accelerator pedal position. Usually caused by rich operation (too much fuel).

Check Powertrain System, if not already completed

Check for possible driver induced causes:

- Owner Complaining About Normal Operation of the Torque Converter Clutch (TCC) and/or A/C Compressor Clutch

Check Ignition System, looking in particular for:

- High Resistance, Open, Shorted, or Arcing Spark Plug Wires, crossfire between spark plug wires

- Contaminated or Damaged Spark Plugs

- Faulty Coil Pack or IC Module

- Check Fuel System, looking in particular for:

- Fuel Quality
- Alcohol Content
- Contaminants
- Water Content
- Sour Fuel

- Incorrect Fuel Pressure

- Fuel Injectors
- Leaking
- Incorrect Flow Rate

Check 4T80-E Transmission operation, looking in particular for:

- Intermittent Torque Converter Clutch Operation.

Check Exhaust, looking in particular for:

- Restricted Catalytic Converter or Exhaust

Check EGR System.

Check EVAP Components.

Check PCV System.

Check for the following mechanical causes:

- Valves Sticking in Guides

- Excessive Oil Consumption

- Camshaft Timing

- Erratic VSS Readings