2006 Audi A8 - error code p0171......probably a vacuum leak.

I purchased brake cleaner to spray to attempt to figure out where the leak is. However I am having trouble identifying where the vacuum hoses are.

Does anyone have a picture and/or procedure of where the vacuum hoses are?

Thanks.

 

Just spoke to a mechanic and he thinks for sure it is an O2 sensor. I will take a look soon. I will try to clean it and if that doesn't work buy a new one.