The following troubleshooting chart resolves erratic performance and no codes displayed. For troubleshooting procedures, refer to the appropriate engine service manual.
Cannot get full power.
- Plugged fuel filters.
- Hose not connected to Turbo Boost Sensor.
- Verify injector calibration(s) are correct.
Cannot get full throttle.
Mis-calibrated Throttle Position Sensor.
Runs rough; misses and occasionally stalls.
- Improper gapping of Timing Reference and Synchronous
- Reference Sensor.
- Fuel leaks.
- Loose battery power, ignition or ground wires. Injector failure.
- Vehicle speed sensor failure.
- Injector harness failure.
- ECM calibration.
Engine idles high after warm-up or hangs.
- Incorrect calibration of Throttle Position Sensor.
- TPS linkage or pedal problem.
- VSG signal wire shorted to voltage source.
Low road speed.
- Determine road speed specifications for vehicle manufacturer data.
- If road speed is less than specified and all mechanical checks are
- correct, then cruise control calibration is suspected.
Vehicle surges or bucks.
VSS may be supplying incorrect data to the ECM.
