Just calculated my gas mileage at 11-12 miles per gallon, OUCH!
4.2l 6 cylinder 5 speed manual transmission.
Gov. site says it should be 15 city 20 hwy.
I have a rack on it but whoa..
172 miles on a a full 15 gallon tank of fuel...
Anyone wanna buy a Jeep??
Since you're in Cali, that means you have to meet regulations, but Ill say this about the 4.2:
I was averaging 15 with my carter carb. I switched it to the MC2150 and went up to 17. I also did the Nutter Bypass and Team Rush upgrade when I did the carb swap. I was running 31x10.5 tires with 3.07 gears. 3" body lift (don't get me started
I did the 8.8 swap. I went to 4.56 gears and a 2" BDS lift. I bumped my mpg to 18. Doesn't sound like a lot, but Ive noticed it in my wallet
. Anyway, since you have to stay compliant, I would do the team rush and check my carter carb out.
Keep in mind also that the government site is showing you what the MPG would be in peak shape. Now that you have age on the engine, lifts, winches, racks, larger tires, etc., its going to dramatically impact your mpg. Not to mention what your gear ratio is. If you have larger tires and a lower (numerically) gear ratio, that'll play in to. You want to be in the power band (around 2k RPM) at highway speeds. If you have a higher ratio with smaller tires, thus running your RPMs up at highway speeds, that'll impact the MPG as well.
All in all, jeeps aren't known for their great MPG. 11-13 seems to be the average for an aged YJ.