My Google-Fu is weak with this one. Searches of this forum and the internet have yielded limited results.

Short and the long is I have a check engine light returning DTC P1077. This is the gasoline V10.

Any ideas about how to diagnose would be appreciated.

 

P1077 is an O2 Sensors reporting that Bank 4 is running lean. I'm not sure what side Audi is calling Bank 4 but I would think it would be on the Driver's side (US models, usually called Bank 2). They may have 2 exhaust manifolds per side on these engines (I've never seen one uncovered in all its complicated glory) and that would make for 4 banks if they're using an O2 sensor in each one. Logic would dictate that Bank 4 would be the rear exhaust manifold on the Driver's side (again on US models) could have a small leak or pin hole allowing air to be sucked in before the O2 sensor location. Getting to the thing to inspect is another story.