i put one on a TJ that i used to have and i as pretty dissapointed the only noticeabole difference was a wistle that got louder as i pressed the throttle.
The simple answer is "no". But that doesn't really answer your question.
Throttle body spacers (TBS) can/may help some engines that have carburetors or throttle body injection. The 4.0's in 94 (I'm guessing that's what you have) have neither of those from what I have been told. They have multiple injectors on the intake and a TBS would not help and could actually hurt performance and mileage.
A cold air intake may be a better choice if you don't allready have one. Plus they make it sound like you're going faster :wings:.
Thanks Guys...I am going to leave it on for our run next week and see how it does...I will be putting about 300 miles on it round trip with freeway driving and then on the trail...If I see it making my MPG's worse I will pull it off when I get down there...Again thanks...