Re: Jumping RPM in 2003 WJ
The check engine light never came on when my TPS was bad. In my case, it seemed much more noticeable when cruise control was engaged, but the symptoms were pretty much identical to what you're describing. I'm not real familiar with the 4.0. The TPS for the 4.7's is fairly cheap, and supposedly pretty simple to install. If the sensor for the 4.0 is cheap, you could always buy one, install it and see what happens. The worst case scenario would be that you have a new TPS that you don't really need.
'01 4.7 Limited Up Country, Front & Rear Addco Sway Bars, Pro Comp MX-6 Shocks, K&N FIPK With 9" AEM Dry Flow Filter