Hey Scotty, I have a 2007 toyota yaris with 225,000 miles. It gets low idle rpm low 600 to high 500 under load (when in drive or reverse, brake applied) or when in park ac turned on. I've done recently new spark plugs, cleaned Mas air flow sensor, new air filter also cleaned throttle body without taking it out did a pretty good job cleaning but still get low idle. Healthy idle seems to be 700 (warm) ac on or off under load with no visible shake like 500 what could it be? No engine codes or anything. When cleaning the throttle body when pressing fully the gas to open I did notice it opening slowly (with clicks) I don't know if thats normal being electronic? Still does that after cleaned car runs perfect other than that low idle problem.