Car Idles Really High Sometimes

I have a 2002 Ford Explorer 4.6l V8 (Automatic). I have this issue were randomly my car will idle high. I start it up and the rpms go to 2500 and eventually get down to 2000 which is a bug jump from my regular 900rpm. This causes my car to fight me when Im breaking as its trying to accelerate even though Im breaking. It also almost feels as if cruise control is on because I can let off the gas and it maintains if not gains speed. I have cleaned the throttle body and it did nothing. I plan on cleaning the iac soon. The wierd thing is if I disconect the battery for 30 minutes then re connect it the problem goes away for awhile. But eventually returns agian. If anyone could help me with this that would be great. Also there is no engine light.