So the car throws a bank 1 lean check engine light every fifty or so miles. When I scan it with OBDII and clear the fault code, the car runs perfect in stock chip setting. BUT if I turn on the APR stage 1 software, the car gets angry. At 80 mph plus in fifth on the highway under hard acceleration, it flashes the check engine light. Obviously, I don't run the car in chipped mode becaues the flashing check engine is really bad news. Any ideas on what this might be? I fixed a vacuum line leak off the fuel pressure regulator and changed the fuel filter.

Thanks,

JPF

 

Check all the vacuum lines. Look at the "L" shaped formed
hose, between the intake manifold and the G-12 reservoir.

 

Please post the actual numeric code.

 

Origonal Part 058 133 783L
Replaced with 06B 133 783 BC
The Audi Parts Dept. keeps these by the sales
window, as they tear frequently.