1997 Polo Idle Speed Very High

Hi everyone, i´m from Portugal and new to the forum so excuse me in advance if i make any mistake or break any rule.
I have a 1997 mk4 polo with engine AER 1.0i. A few days ago i took out the throttle body to clean it since the engine started to stall i figured it was dirt around the valve. After putting the throttle body back in place it stopped staling but now i have the opposite problem, now every time i use the clutch wile riding the car instead of going down to correct idle speed (around 800 rpm) it stays at around 1800\2000 rpm and then slowly goes down. I used the diagnostic machine at my school and it gave me an error (Idle speed limit exceeded). I erased the error but the problem persists and the error doesn't show anymore. It´s very annoying having the car "roaring" at traffic stops or crosswalks.

Thanks

Paulo