Rough idle at 600-700 RPM's

When at 800-900 rpm idle is fine (put my foot on gas with other foot on brake to achieve smooth idle). Problem seemed to first begin when I had a throttle body error
i cleaned the throttle body by removing the throttle body, but I did not disconnect the battery (you website says this may cause problems).
immediately after cleaning the throttle body my vibration problem increased
the vibration gets worst if I drive in a stop and go fashion (traveling in the city) for extended periods, like driving for UBER.
Dealer said that clutch fan was problem, replaced clutch fan with no change in vibration. Alternator is now overcharging, but the vibration was a long time before the alternator problem. This problem has become worst over time, 3 years.
Very experienced mechanics haven't been able to help me.
Help please!