Funny that you ask this. I'm actually currently doing a little experiment to see just how much improvement in fuel mileage I'll see from obeying the shift indicator for a whole tank of gas. Keep in mind, I have 4.11 final drive and 31.5" tires (not too far from stock), and I'm seeing an average of 15 mpg city driving.My DD is a ‘99 4.0 manual TJ. Just curious if any actually shifts according to the indicator on the instrument panel? I find that I can’t even get up to speed with the flow of traffic if I do!
So far I've noticed that the indicator tries to keep RPMs as low as 1300 if I'm not trying to accelerate at all. It's moved my shift point about a whole 10 mph lower from how I usually drive. I'm eager (and probably a bit too optimistic ) to see the results next time I fill up and calculate fuel mileage. And I'll be sure to update the thread with my findings.