At the insistence of the Toyota service center, I had throttle body service performed, despite having no throttle problems. Now, there is slight engine shaking when idling and most especially the idle gets stuck after cold start when driving in gear and then going to neutral on stops. I have to hit the pedal to try and bring it down. Problem is non-existent when engine is warm. Service rechecked throttle and also cleaned IAC valve. Health check performed and no diagnostic code registered. Now I wish that I hadn't done the service to begin with. Please help! Thanks!

 

Probably mis-cleaned the IAC. Any little dirt in there can cause problems. You can clean it yourself without too much of a hassle... or bring it back ? :/

 

How High is it idling? And how far does it come down?

 

Whatever RPM it is on when I shift out of a gear, e.g., 1st, 2nd, 3rd, etc. into neutral, especially after cold start. The problem seems to go away as the engine gets warmer, but it even occured after a long drive. The idle is steady @ 700 RPM, however, slight shaking when in neutral can still be felt. This never occured prior to the throttle body service.

 

I would Say take it back. Make them See it and fixit..

 

I ended up paying for a new IAC valve, despite telling the stupid Toyota managers that there was nothing wrong prior to throttle body service. However, the idle still continued to get stuck over 1,000 RPM after letting go of the gas. The master tech reinspected the new part and cleaned the linkage. It makes me wonder if I really needed a new valve in the first place or was conned into buying a new one?