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.