Originally Posted by dane.p
My jeep over revs so bad, so I was just wondering if I shift before it hits 2500rpm or 3000rpm, will it save gas or will it waste gas?
You have an auto trans. Unless you have major modifications and the stock shift points don't cut it, or are towing, its best to leave it in D.
Gas mileage cannot simply be based on rpm, although rpm plays into it. Its a function of load, rpm, and vacuum.
The 3.7s and 4.7s tend to wind up some before shifting so as to offset their lack of low end torque.