96 Camry 4 cyc rough idle
 

I recently purchased a 96 camry with 120,000 miles from a one owner. The car prior to my purchase just had a new timing belt installed. Plugs and wires are good as far as I know. The Problem: After the car warms up, regardless if in park, neutral or drive has a rough idle where the tach hunts 300-400 rpm. Outside of that it runs as good as a new car. All motor mounts have been checked and the only bad mount which I am going to replace is the torque strut mount. I have had some suggestions to look for a vacuum leak to the local toyota mech said inside the throttle body is a spring and slide that gets carbon build up. Suggested cleaning with brake cleaner. Thougts?