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:

• Perform VISUAL/PHYSICAL INSPECTION .
• Ensure driver understands operation of A/C compressor as explained in owner's manual.
• Check vacuum hoses for leaks or kinks.
• Check for intermittent EGR valve and solenoid operation.
• Ensure proper Vehicle Speed Sensor (VSS) and speedometer operation.
• Ensure correct O2S/HO2S operation.
• Check fuel pressure while condition exists.
• Drive vehicle at speed of complaint and using scan tool, monitor fuel trim. If condition is lean, long term fuel trim will be more than 20 percent. If condition is rich, long term fuel trim will less than -20 percent.
• Ensure adequate secondary spark is available.
• Verify ignition timing is correct.
• Ensure sufficient secondary spark is available.
• Check PCM ground connections.
• Check condition of spark plugs.
• Check for defective spark plug wires.
• Check for restricted exhaust.
• Check for Manifold Absolute Pressure (MAP) sensor scan tool parameter being fixed or slow response when throttle snapped.
• Check charging system output voltage.