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

 

You posted this back in October, is this still the same concern or something new?

 

Yes,but since then I cleaned the Throttle Body and changed the Fuel Filter.It idles perfect now until you turn the heat or air on.I have a friend coming over tomorrow to look at it ,he thinks it is a vacuum line.He has a 05 CTS and he just ordered a new 08 CTS and met someone that invited him to go see his CTS being built on the line in Lansing,he said it was really cool they called him the other day and said I have good news and bad news.The good news was your car is being built and the bad was it is today meaning yesterday,so at 8:30am he drove to Lansing which is about 2 1/2 hours away.He said a PR girl took him and his wife around to different parts of the line watching his car being assembled,all the line workers where super nice shaking his hand thanking him he bought a Cadillac.It was a special order,he did not want the all-wheel-drive.Black on Black should be here Friday.

 

I had the dealership update my software to raise the rpm about 50 rpm. This is a known problem on the 03's.