[Audi 80 ABK 1993] Throttle position sensor - adjustment. How?

Hello!

I have little problem with my Audi 80 ABK from 1993. In idle state on
warm engine it has between 950 and 1100 RPM. When I press clutch engine
speed drops to 1100 RPM and then slowly drops to 950 RPM. I suppose, it
is nothing good.

So... I decided to check TPS with voltmeter. I messured resistance and voltage.

Measurements:

1). Resistance (ignition OFF):
- 1 and 2 pin - Closed throttle: 1.35 kOhm. While opening it suddenly
drops from 1.35 to 1.20 and then increases linearly from 1.20 to 2.53
kOhm (full opening of throttle),
- 1 and 3 pin - 1.91 kOhm,
- 2 and 3 pin - Closed throttle: 3.10 kOhm, decreases to 1.35 kOhm (full opening),
Correct values?

2). Voltage (ignition ON - engine OFF):
- measured on 2 pin - Closed throttle: 0.65V and increases linearly to 4.20V (full opening)
Correct values?

Someone in polish forum told me that 0.65V isn't correct value and I
have to adjust TPS. In ABK produced after 1994 it's done with VAG, but
before 1994 (like mine) with voltmeter. I have no idea how to do that
and what voltage should be.

Any help?

Thanks for your time.
Greetings from Poland,
Rafal

PS. Sorry for my english.

Thanks for reply. Will try this procedure - BTW: first I hear about this.
Also, in the weekend, I am going to clean all ruber tubes around throttle and make sure that there is no fake air. I won't forget about idle control valve too.

I have another question. What do you think about that procedure:
- disconnect battery clamps for the night,
- in the morning start the engine and wait until fans turn on,
- stop the engine,
- adaptation is done.

Is this correct for ABK? Does it change something?

Oh, I have forgotten one thing. The problems about RPM's in idle state occured after ignition coil replacement. My old one has broken.
Don't know if there is any relation...

In this weekend I have cleaned rubber tubes around throttle, idle control valve too. Also I didn't find any holes, leaks, etc. in installation. The problem still exists. RPM's hang at 1100 and slowly drop to 900-950. Sometimes it bounces again to 1100.

I have this issue since ignition coil replacement (six months ago). Couple weeks ago I went to a friend with VAG and there are no errors.
RPM-meter is OK. Its values are correct. Same in VAG and on dashboard.