Toyota Pickup 4X4 2.4L idles fast and engine surges

1991 toyota
pickup
4x4
2.4L 4 cyclinder
5 speed manual trans
180k milage
no air condition

Hello, truck runs fine except at idle when warm. After warm up the truck idles fast and when brakes applied, engine surges. I checked the vacum line to the brake booster, by disconnecting but still idle is fast. I adjusted the idle speed mixture jet on top of throtle body but even with jet screwed all the way closed it still idles fast. I checked the coolant level and it is completly full. I am stuck, please help.
Paul?