I have a 89 YJ with an automatic and I have the idling problem but there is a fix for it is this forum within the last 45 days or so.
There is also info addressing this @ http://www.off-road.com/jeep/tech/engine/carter.html
Ther is a great amount of info on the fix for this system. Also check into the Juice Box ignition system. With both of these modifications it should aid your stiuation greatly at a cost of about 120.00 +shipping.
So far I'm happy with my Jeep but it will be much better when the mods are done. As far as the automatic goes it works well off road crawls realy well, but I'm not doing realy radical stuff like some of these guys cuz I have to drive it back and forth to work. Eventually I plan on adding a 4.0 head they say this will add about 40 HP. These things realy are under powered with the auto trans, but it sure works great off road.
89 YJ about to get Juice Box and carb fix 4" lift 2"BL 33" swampers