Igot a2007 3.2 avant. Whenever the weather had some big changes, like 15 degree drop in two days.
My engine acting funny. During the engine cold startup but it stayup at200 rpm unless I manually give somegas.
Although it happened in more than a dozen times,the dealershipclaimed it is okay after their whatever computer check up.
After the conversation, the dealer blamed on the gad that I put in. Since the day one that I got my car. I always fill it up with premium in Shell.
Same station, same gas, I got no problem with my old2002 3.0 sadan.

Can someone please help me to solve this puzzle?