Audi Repair: RPMs up and down when car is stopped and in neutral, throttle plate, manual transmission

Question
QUESTION: I basically know nothing about the workings of a car but I have noticed something unusual about my 2001 A4 1.8L T.  For example I am stopped at a stop light, my manual transmission is in neutral and my RPM's quickly increase from about 1200 to 2200 sit at 2200 for a few seconds and then quickly drop back down to 1200.  This continues in the same pattern until I put the car back in gear and continue driving.  This has never happened before and it makes me feel like something is wrong.  Any ideas?

ANSWER: hello
I have seen it many times on all 1.8T engines. Most of the time throttle plate is dirty and after you clean it , problem goes away. Sometime it needs to be adapted. Any body can clean throttle plate, just make sure key is OFF, remove big hose than comes to engine and clean it inside. You can open it with your finger and use any brake or carb clean with rug.
good luck          pltech

---------- FOLLOW-UP ----------

QUESTION: What do you mean by with rug? And if I do use those cleaners should I be rinsing the hose out afterwards, being that those cleaners are very flammable?

Answer
hello
I meant cloth any cloth is good. Just wipe it and make sure is clean on both side of plate. Spray on the cloth , and wipe it, you can spray inside but not much.
If you spray a lot just let it seat for 10 - 20 min. and you will be OK. NO RINSING>>

good luck          pltech