I have the mikuni carb and evt intake that I had installed.... It idles around 900 - 1000 rpm's. When I open the throttle and then let it go, the rpm's come back down to around 1400 then slowly comes down to 1200 rpm's.... The only way it goes back to an idle of 950ish rpm's is if i push the throttle on the carb itself back to close. What can i do?

More than likely its your throttle cable, First thing I'd check is the way its routed and make sure you don't have to aggresive of a bend.

If not then its either sticking and needs to be lubed (3 in one oil will fix you up) or it has brokin strands and its unraveling inside the sleeve causing friction.