It's probably a vacuum leak. Check the vaccum lines or have someone who can to do so, they can become cracked or broken and cause the symptoms you have stated. Sometimes, depending on the size of the vacuum line you can hear a hissing noise under the hood where the hose is cracked/broken. A vacuum leak will not cause a check engine light unless it goes to an emissions component that functions on vacuum. It a vacuum line is not the case then you need to try cleaning your throttle body and IAC unit.