I own a 2007 Chevy Aveo5, After starting the car the rpm's shoot up to 3000-4000. I did some research and came up with it being the TPS which is on the Throttle Body. I purchased a new one and installed it, ran it through the " Relearn Procedure " But it still Elevates to 3500 rpm's while idling, I took it for a little drive and as soon as you shift it into gear the Idling drops down to about 1000 rpm's and is really boggy, It drives but acts as if it has no power while driving.

 

A vacuum leak or faulty MAP sensor could keep the idle high.

Try to locate leak . Lots of info out there on how to.