OK so I have a 08 cobalt SS. Stock other than a k&n typhoon intake. I've noticed at cold start the rpms sit a little high and sounds like the turbo is building boost or something. Wasn't sure if this was normal or not.

 

Yep, thats called cat warm up. It builds slight boost to put heat in the cat early for emissions purposes. Perfectly normal. It can be turned off via tuning if it bothers you.

 

OK cool thanks