Just doing a post for a friend of mine, he has a 2005 BMW 530i that he's concerned about. It seems to be getting an average of less than 12 mpg according to the gauge, and he noticed that it's going through way too much gas during normal driving situations. There doesn't seem to be a leak of any sort, but he also observed that the engine itself seems to be strained as has trouble maintaining speeds like it used to. It also hangs on revs more than it used to, even during light driving. If anyone's got any insights on this, we would really appreciate it. Thanks!