Take your sensor out, and take off the intake pipe, get some throttle body cleaner(Intake Medic by Gunk works) and clean out your Throttle body. Failing that, check to see if the sensor that's on the intake pipe is actually properly connected. Also, check for any vacuum leaks, these leaks could be at the intake manifold, throttle body or EGR Valve flanges. And, even for a laugh, check your PCV Valve.