Is it possible to log the MAP sensor and N75 valve to see if they are failing?
 

I am wondering if there is any particular values (eg. voltages) which would let me know if these two parts are working properly. The two parts currently in question are the manifold absolute pressure sensor in the throttle body boot, and the vacuum solenoid valve. If so, what should be logged and what values should be looked for? Which blocks in vag-com?

I am trying to solve a boost cutoff issue which is occuring at roughly 5000rpm. No codes in vag-com, but logs of actual vs. requested boost show a huge droppoff in requested boost at roughly 5000rpm. This, in turn, causes massive throttle cut since the actual boost is considerably higher than the requested after this dropoff.

Thanks, I've outlined the boost cutoff in yellow.
<img src="http://pictureposter.audiworld.com/43942/issue_2.jpg">
<img src="http://pictureposter.audiworld.com/43942/issue_1.jpg">

measure the voltage from the map to the ecu. the more resistance value change the more V is sent.
 

find out how much voltage is being sent to the MAP.

when you add more pressure to the manifold the more the resistance value changes.

with that. the voltage is sent back to the ecu.

i don't remember off the top of my head what the voltages and resistance is. i'll see if i can get these numbers for you.