Engine Surges And/Or CHUGGLES
If engine power varies or vehicle feels like it is speeding up and slowing down during steady throttle operation, check the following items:
- Check vacuum hoses for leaks or kinks.
- Check for proper Torque Converter Clutch (TCC) operation.
- Check EGR valve and solenoid operation.
- Ensure correct speedometer operation.
- Check fuel pressure while condition exists.
- Check in-line fuel filter and replace if dirty or clogged.
- Check fuel for water contamination.
- Determine if condition is caused by a rich or lean system. Using Tech 1, measure O2S/HO2S output voltage while driving vehicle when condition exists. Voltage less than .45 volt, indicates a lean system. Voltage greater than .45 volt, indicates a rich system.
- Check O2S/HO2S operation and for RTV sealant or silicone contamination. Also check for sensor cracking or glycol contamination. This will cause a false high voltage signal to ECM. ECM will respond by reducing (leaner) air/fuel ratio.
- Verify ignition timing is correct.
- Ensure sufficient secondary spark is available.
- Check ECM ground connections.
- Check for faulty spark plugs.
- Check for defective spark plug wires.
- Check for restricted exhaust.
- Check charging system output. Repair charging system if voltage is not 12-16 volts.