I installed a Magnusson Supercharger on my '11 CoD 4dr Rubicon, re geared w 4.56', 35" Pro Comp Extreme A/T's and tuned with Diablo tuner.
Everything works well, speedo, shift points, etc.
The Miles remaining and MPG however are out of wack.
Any known remedies?

 

The MPG and miles to empty have never been accurate in any vehicle I've ever driven. Ever. The algorithm the factory uses to estimate this info doesn't change when you tune the computer, so there wont be a fix.

What is the issue? Estimating too high or too low? It could be that the tire size programmed in isn't quite right