I have changed both,

PCV at 109485K 7/17/2011


MAF Check Engine on 121608K
1/6/2013 17536 - Fuel Trim; Bank 1 (Mult)
P1128 - 001 - System too Lean - Intermittent - MIL ON
17538 - Fuel Trim; Bank 2 (Mult)
P1130 - 001 - System too Lean - Intermittent - MIL ON
Readiness: 0000 0000

Cleaned MAF and cleared the codes worked for a while but ended up changing it 300 miles later

Thank you, so it really seems like the MAF could be the culprit. I have 135k miles on the car too so it could be the original MAF.

GREASE - So did replacing the MAF clear both codes?

*UPDATE*
Unplugged MAF with the car off, then turned the car on and it idled exactly the same. Sounds like it could be the MAF now, the car "should" have run crappy with it unplugged.

Yes changing the MAF worked for me.

my PCV is fine. I can find no vacuum leak there. no sucking sound.
I've cleaned my MAF sensor twice now with CRC MAF sensor cleaner. lean codes came back after a short while.
How'd the new MAF sensor do you ?

The new MAF didn't get rid of the codes, they came back :( I have a pretty bad exhaust leak from the flex pipe so that will be my next thing

Sounds like you are both hitting a road block. Perhaps one of the Audi Techs on the site can help.

P1573 - Left Engine Mount Solenoid Valve (N144): Open Circuit
P1575 - Right Eng. Mount Solenoid Valve Short to B+
P1874 - Valve for Torque Support Mount: Short to Plus

I also get the above codes along with the lean codes below... The lean codes are the ones that trip the check engine light.

P1136 - Fuel Trim: Bank 1 (Add): System too Lean
P1138 - Fuel Trim: Bank 2 (Add): System too Lean

Grease - I've tried. No answer so I assume they don't know. I think they are more familiar with the smaller cars. Was really hoping the MAF was it. I've also replaced the fuel pressure regulator with no improvement.