Low power and stalling when idling low

[lilacjam]

Hello everyone, 

I'm new here and I would really appreciate your help as I have been to many mechanics trying to solve this problem. 

My vehicle when i am idling in traffic drops rev, stalls and sometimes shuts off. Other times when the rev drops it idles erratically  between 1 and 2 on the rev clock, then the engine light comes on and the rev is constant above 1 on th rev clock, when this happens the brakes feel tough. I read about adjusting the throttle pot but I have nor tried it. 

My current mechanic has checked the engine and cant find anything wrong. He has also cleaned the intake with carb cleaner.  I can attach video if anyone is interested. 

Has anyone had this problem before? I will greatly appreciate any help.