rough idle

I own a 2002 caravan w/3.4L engine. It only has 6000 miles and it is starting to develope a rough idle.It runs fine otherwise.Before I bring it in for service,can anyone give me some suggestions why?I know there is probably a hundred possible causes but I figure someone else may have encountered the same problem.
Most of my driving is local but I do get it on the highway about once a week.Any advise is appreciated .

Jimbo,

Did you ever get this idle situation resolved?
My 02 with 3.8 does it only stopped and in gear.
It does not shut off, but runs rough for awhile (rpm drops to 500) and then somewhat improves(idle jumps to 700 rpm), but never really smooth like when it was brand new. I have 12,000 miles on it and it has done it for at least the last 6K. I have taken it in to be looked at, but the tech says it is idling in specs. and nothing is wrong with it. The throttle position sensor has been replaced and the TB cleaned, but still does it. Of course, it will not act up for them like it does when we are driving it. Dealership placed a on-board computer in the vehicle so I could capture this condition when it happens for study by Dodge for possible fix. Service Dept. stated they have nothing to go on to fix the problem. Their equipment shows no problems at all. But it does it. My friend even noticed the other day riding around. "He stated, what is wrong with your van? I said if I knew, I would tell Dodge how to fix the problem" Frustrating, and even more to the wife, who takes it out on me!

Please share your experience, sounds like we got the same situation.......................thanks!

Could you be experiencing an out of balance rad fan??
Have fixed quite a few 01's with this condition. The only time you notice it is when the rad fans come on when idling in gear.