Had a similar issue and
Had a similar issue and simply removed the throttle body,cleaned it with a toothbrush and throttle-body cleaner and voila, good as new. Your dealer will gladly charge you $950.00 to unnecessarily replace the throttle body. It's easier for them to replace it than to take the 20 minutes it takes to clean it. It cost me about $8.00 and 40 minutes!