Chrysler Repair: idle issue: code 0172

Question
I have a 2001 Grand Caravan with 3.3 l engine.  It threw po401 code, so I cleaned out the carbon from the egr tube, the egr valve was replaced 2 years ago and seemed clean.  This solved that code, and idle seemed fine till the next day, when
really rough idle and stalling once warmed up.  
Now it throws a po172 code only.  Seemed to idle fine when I started it in th morning, cold outside, at 1000 rpm, then once warmed up, rough again and idle fluctuates between 500 - 700, and stalls sometimes when starting warm after running for awhile.
I cleaned the EGR valve with throttle body cleaner, stem seems to move freely with  screwdriver pressing from the bottom.  When I turn the valve upside down, something inside rattles, like a loose coin. Checked the lower vac hose to the valve while revving the engine and can feel the vacuum. There is some movement I can see in the area where the slit exposes the diaphram.
I read that I should check the PCV valve, but didn't do that yet, since it seemed quite difficult to reach, being located on the rear intake cover.

thanks,
Gary

Answer
Hi Gary,
The rattling sound from the egr is suspicious so you might want to remove it and see if you can determined what is causing that.
As to 0172 I can copy some pages from the powertrain manual and attach those to an email I would send to you directly. When you tell me your email address don't use the @ symbol instead use "at", or the address will be automatically erased from the message. There are a number of possibilities for that code.
Roland