Clean or replace your IAC, all of your symptoms point to that being the issue.
Bad temp sensor can result in hard start issues but its not common. Bad cat is easily tested by removing the front 02 sensor or drilling a hole before the cat and testing for pressure.
Vacuum leaks will cause rough idle and could give various random error codes as the computer will sense the mix is now lean and add fuel trying to compensate.
Last edited by blackvan; 02-20-2014 at 03:33 AM..