The results were error code P0171

Definition
Fuel Trim Bank One Condition

Explanation
The powertrain control module uses the oxygen sensor to calculate the air/fuel ration of the engine. The computer has recognized a rich or lean condition on one engine bank only.

Probable Causes
1. -If bank one and two codes set together suspect fuel pressure or MAF sensor.

2.-Oxygen Sensor Defective

3. -Ignition misfire-repair.

4. Fuel injector problem.


That is exactly what the printout says; any advice as to what I should do?

 

Bump?

I guess if I get nothing ima start at the o2 sensor, I wanted them to get rid of the check engine light to see if it came on from having low fuel, but they wouldn't do it

 

That code from Bentley is a lean fault code, not rich.
If this is a 2.8L than you most likely have a vacuum leak on the passenger's side, or towards the back of the motor. Go over all your vacuum lines with a fine tooth comb then report back. Changing you O2 sensor shouldn't be changed until you fix the visual and most important thing "cheap" repairs first.

 

Doh, I always forget to post that I drive a 1.8t a4

 

Add a signiture.