Lack of Power/Sluggish/Spongy/Stumble

DEFINITION:
Engine delivers less than expected power. Little or no increase in speed when accelerator pedal is DEPRESSED part way.

Check Powertrain System, if not already completed

Check Fuel System, looking in particular for:

- Fuel Quality
- Alcohol Content
- Low octane Level
- Contaminants

- Incorrect Fuel Pressure

- Plugged or Dirty Fuel Filter

- Fuel injectors
- Incorrect Flow Rate



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

- Knock Sensor Not Operating Properly


Check exhaust, looking in particular for:

- Restricted Catalytic Converter or Exhaust


Check EGR System.


Check for the following mechanical causes:

- Camshaft Timing

- Low Engine Compression

- Throttle not Opening Fully

- Restricted Air Induction Flow

- Vacuum Leaks in Intake Manifold System

- Erratic VSS Readings

- Erratic Engine RPM Readings


Check for possible driver-induced causes:

- Vehicle Displaying Normal Power