Hello again y'all. My mom has a 2007 Mustang with the 4.0L V6 and 29,000 miles on it. Well, since our truck has been acting up we can't get any of the cars in the garage due to where the truck is sitting. So we've been parking the mustang in the driveway. Well, ever since then, she's complained (she knows a bit about cars, so its not unfounded) that it's been running worse then usual. Well, today we went out, and it is indeed vibrating more at idle, and the idle speed hops up and down a little bit in park. She says she thinks its because it's been getting colder. Well, I dunno about that. It does it even after its warmed up. It has whatever dino oil and filter jiffy lube put on it when she took it to them ~ 1800 miles ago.