'99 WJ 4.0 with the same mileage as original poster.
When I first got my jeep, I posted a poll about mileage, and people were generally getting a lot better than I do.
I'm very light footed, I don't race people off the light etc. but doesnt seem to help me much.
I recently installed a K&N FIPK, which definitely helped with the throttle response, but as of my last fill up it didn't do anything for my mileage, but I'm going to give it another month or so to see.
I'm also pretty anal about tracking gas and mileage, I even have a little excel file that does all the work for me
Next on my to do list to try and improve my gas, is switching to mobil1 (10W-30 + mobil1 filter).
And after that, MAYBE a tornade fuel saver.
And before you all start with the " that's a load of crap, don't waste your money" posts.
...all the posts i've read that ***** about this little device, are by people who've never used them, and those who have are a mixed bag.
One guy over at ju actually saw a 3mpg jump on his 5.7 , but he put his right above the throttle body, and not at the end of the intake right after the filter (which is what tornado tells you to do).
with a 30-day money back policy, I don't mind paying a little shipping to try something that may imrove my mpg...