Can you baby a car too much? I tend to drive my truck gently, lots of highway miles, and am so careful about it that the Nissan 2.4L RARELY gets above 3K rpm's. Am I doing my engine a favor by keeping it "on the down-low", or should I get it up and going on a regular basis? This is not necessarily the same thing as the "italian tune-up" we talked about on another thread, just a general daily driving question.