For 1990-2009 cars

Definition: Engine power variation under steady throttle or cruise. Feels like vehicle speeds up and slows down with no change in throttle position.

• | Check misfire counts using Scan tool (if any exist).

• | Verify proper TCC operation and customer understanding of TCC.

• | Verify proper A/C clutch operation.

• | Monitor fuel trim values on Scan tool for system running lean (short term fuel trim is significantly positive).

• | Monitor fuel trim values on Scan tool if system is running rich (short term fuel trim is significantly negative).

Check:

• | Generator output voltage

• | Vacuum lines for kinks or leaks

• | Fuel pressure

• | Spark plugs for cracks, wear, burned or heavy deposits on electrodes

• | Fuel quality