Hello,I have a 03 CTS 3.2 liter 57,000 miles,lately it has been idling rough when sitting in Park.I just cleaned the Throttle Body and replaced the Fuel Filter and it is 100 times better, but when I turn the heat or air conditioning on it idles rough again.Any ideas?,your help will be much appreciated.Thanks

Honestly you will get alot better response in the actual CTS forum. No one comes in this section much, not sure why? Do a search first. This helps as some quesitons get beat to death and do not always get good responses in these cases.