Grand Cherokee CRD and proper idle characteristics

I recently purchased a GC CRD which is the first diesel I have owned.  The following problem I am about to describe has been determined to be a non-issue by 3 dealerships.  I would like to know what others have experienced regarding this matter.  
PROBLEM:  Upon deceleration from anything above 2K rpm my motor will rev down to 1.5K rpm and hold right there.  I can travel 1 or 2 city blocks before the weight of the vehicle plus engine compression will slow the motor down to 500 rpm.  When coming to a stop it takes quite a bit of braking power to quickly bring the motor speed down from 1.5K to 500K rpm.  I concider this dangerous, when coming to a stop.  I am use to a gasoline engine which easily revs down to 500 rpm when coming to a stop.  all the dealerships contend that this is normal for the CRD.  Is this true?
Thanks for any input.  

I haven't noticed any problems like that with mine. One of the problems I have noticed with this engine is that there is not a lot of experienced mechanics. Try finding someone in your area that has one and see if you can drive each others around the block for a test ride.  
08 WK CRD, FS. 2500 bypass oil filter, ARB bumper

I do know the driving characteristics on diesels are generally pretty different than gassers. I think that engine has a variable-vane turbo, so it might have something to do with the vane actuators.

Remember that diesels don't have a throttle plate like gas engines do, so when you let off the throttle, they may not immediately drop revs like on a gas engine. A lot of older diesels drop revs immediately because they have a mechanical throttle, but with these newer, electronically-controlled engines, the computer makes a lot of the calls, based on emissions, programming, ambient temperature, etc.

I'd say try to find another model in your area, either a friends, or test-drive another one off the lot, and see if it does the same thing.