What you're hearing is called signal noise. It's the "radio waves" that eminate from all the elictic things in your jeep. For instance the electic motor that runs your heater makes alot of signal noise.
The way I fix it is to limit the legth of wires I use for my radio and make sure the antenna wire and power wires are really mounted well.
The first thing you need to do is check which part of your CB is getting the noise.
1. If you have a PA wire, unplug that and listen for the noise.
2. Unplug the antenna wire (DO NOT KEY YOUR MIC!!) and listen for the noise.
3. unplug the power cord and listen for the noise( just kidding)
3. Take another set of power wires (12v and ground)and mount those into the fuse box out under the hood or directly to the battery. listen for the noise.
4 Take off that temprary ground connected to your fuse box or battery and use the one you have mounted to the bare metal of the tub below the center console.
Odds are, if it's not the antenna wire it's that ground.
If it is the antenna you might look at where it's routed. Is it near a heater blower? running it through the dash will take it close to lots of noise generators. Make sure the outer part of your coaxial cable is grouned too. Although I think if you have it plugged into the radio it should be the same as the ground in your power wires.
if it's the power lines shortening them as much as possible is good. Other than that you may need to get an RF Choke. I'm sure radio shack has them. I'm not sure what other people do.
Anyway.. Good luck.