I have a 1997 2.8 quattro. P1106 came up. Reviewed couple threads and all suggest its pre-cat o2 sensor. How hard is it to change it myself?

 

That code is defined as either low voltage on the driver side pre-cat O2 sensor or an air leak. The air leak is a low-percentage chance so yeah, the O2 is the most likely. It's not too hard to change - unbolt the coolant tank and tip it out of the way and you should be able to get to it. You need an O2 sensor socket and probably at least a 12" extension to get it undone.