miguel rodriguez

I have a 04 Chevrolet teacker that i took out the complete throttle body and cleaned all the inside and i also removed the sensors. After i gotta done, the engine started to accelerate for a long period and now when i start the engine cold the rpm stays up at 2000 then drops little by little. Ones i switch to reverse, the rpm drop from its position til the engine turns off. Now i can get it fix and still trying to find the problem... can some one helps plizz!!!