s5 tii problem anyone
 

Ok let's start by saying this I drive the car for sometime when it's in ok temperature but after boosting a cup please of times it starts dying low rpms,starts bogging, backfire a lot, well anyways I wonder what could be the problem of anyone has an idea please share it with me,
I try to look for vacuums leaks with no success also rps stay in 1500 and 1700 but after driving it it goes to 700 or 500 what could it be?
I'll post a video when driving it and at idle for better description thanks for any information about this issue

Have you pulled codes?

Have you checked the water thermosensor?

Does the car idle high when in neutral or in gear and does this occur just after starting a cold engine? Does it idle high after starting a warm engine?

Here's some videos of the problem

https://youtu.be/lfupU-8dbX4

I really don't know how to pull the codes out I try but I got lost and really confused

Ok here's a cold start

https://youtu.be/aUcCkjN3QyA

To pull codes you locate the Green check connector near the lead coil which has but one wire which has an Orange color. Ground this wire to the negative battery terminal and w/key to on the CEL will spit out any error codes.

Here's an alternate theory:
The thermowax is maladjusted or defective.

Here's the scenario...
As the engine coolant warms, the thermowax piston extends and ultimately the linkage allows the throttle plates to rest on the stops...this is your idle state.
If the pellet action is jerky or the piston stroke/linkage sticky, your idle may have been adjusted when the plates are not actually on the stops...the thermowax is acting as hot idle control (which it shouldn't).
As the engine gets hotter, in this scenario at some point the thermowax moves again and the plates close even further, beyond the conditions the ECU considers baseline idle.
This will bring on the BAC and engine surging as the ECU tries to compensate for the new low idle speed.

It's a possibility.

So should I removed it or something? What can I do to adjust and we're it's there thermowax?

Back of throttle body