Questions and Answers

Pontiac Bonneville DTC P0171 Q. Hi, I Have a 1994 Pontiac Bonneville SSEi Supercharged. The check engine light has come on. I have had the car checked, but at a transmission shop. The code was "P0171 fuel trim lean". Could you please let me know what part to replace to fix? The car has a 3.8 liter V-6 with 125,000 miles. The car runs fine but will stall sometimes. Will start up right away. Also, if I leave the A/C on too long, the car starts to surge.

A. I have no crystal ball to tell you what needs to be replaced. The factory service manual has a chart to help in diagnosing this code. A lean code means the O2 sensor is seeing a lean condition. Vacuum leaks? Clogged fuel filter? Lots of maybe's. Have someone check it out with a diagnostic chart following ALL the steps in order.