Automatic Golf keeps stalling

Hello everyone,
I have MK 4 Golf 1.6auto, T registration, AEH engine 90k miles.
Few months ago some problems stated to emerge and gradually they got worst:
1. Oil leak
2. Unstable idle revs on the warm engine (after 20-30min drive). In idle mode revs are dropping to 6000and get beck to 8000.
3. Car got stalled several times while stopping at the traffic light or in a traffic queue.
4. Average fuel consumption is 24mpg which is very poor.
5. Sometimes, after stopping car appears to be “blocked” in place, so I accelerate more than usual and it jumps forward heretically.
6. On the cold engine when revs are not playing up, break pedal appears firmer (and works better) than on the warm engine.


I am planning to clean throttle body, clean all the hoses in and out, and change Air Mass Metter and Air Filter.
I know from this forum that throttle body and car computer to be reset to basic settings after all cleaning is done. Can anyone tell me how to reset this staff? How can I obtain faulty codes from the car?

Any ideas and help would be much appreciated.