So... this is the latest code my '11 Optima is throwing. Just had a throttle body cleaning done when they replaced the engine just under a month ago. Did a visual vacuum line inspection and didn't see anything noticeable. I stopped at the dealership this morning and they squeezed it in to look it over. They are doing a goodwill throttle body replacement and hoping that fixes it. Seriously! You don't have a definite diagnosis and are just going to start throwing parts at it. Do mechanics know how to diagnose a problem with multiple possible causes anymore when the computer doesn't tell them the exact answer?