I was driving to work this morning with the a/c on. Everything seemed to be running fine. But when I finally got off the freeway and turned off the A/C, I noticed there is a more than usual vibration at idle. The needle is sitting between 500 - 1000 RPM. But there is definitely a vibration. What do you guys think is causing this rough idle? Dirty throttle body? Dirty IAC motor? anything else I should check?

thanks

 

Motor mounts

 

just a little update. I went for a drive during lunch today and the engine light came on. I bought a OBD reader and i got a P0404 code. So this is not a motor mount problem.