I have a 190e 16v 86mbz. IM having trouble with the IDLE! The trouble was born after I had clean the throttle valve housing. This caused my IDLE to rise and stay at 2000rpm. I was able to bring it down to 900, but my IDLE is rough now, the car turns off on me at least 2 times every morning before staying on, and you could feel a sort of drowness when flooring the gas pedal before feeling any power. "I was able to bring it down to 900rpm by turning a tiny hex nut which I believe controls the position of the throttle valve". ( I took it to a mechanic, and he said I needed an IDLE CONTROL RELAY which runs for about $285 ) Could anybody give me some suggestions?

THANK YOU, P V M