Larger tires/stock gears directly affect MPGs. Larger gears change the rotation speed of the axle per rotation of the driveshaft getting that ratio back to a stock ratio resulting in much better MPGs. If i recall correctly. Heres a chart. As well as a lift requirement chart.

 

You have never had to pull a check-engine light while on the road?? If not, consider yourself lucky.

For me, it is cheap insurance. If I get a CEL during a blizzard, at night time, I either need to keep driving and hope that it is not serious - or get out of the truck and start looking around not knowing exactly what the issue is.

With a cheap OBD bluetooth scanner, I simply pull it out of the glove box and read the code without even having to unbuckle my seatbelt.

Jeep's dont have the best codes, but it at least gives you the peace of mind of knowing what the issue is.

 

No check engine lights?

 

I run an Ultra Gauge in mine have for quite some time a very useful tool and I have it running to monitor all the time for some functions. Mounted to the bottom of the windshield.