Anybody know how to adjust the throttle position sensor? Is that something that we can do without "special tools"? I'm still struggling with suddenly crappy mileage. Already got new oil, plugs are clean and fairly new (only about 2K miles since they were changed), tire pressures are good. So I'm out of ideas...used to get consistent 40mpg, now it's 35 if I'm lucky. I'm not beating on her any more than I ever have, so I don't get it.