Re: 2008 Grand Cherokee 4.7 resting idol concern
The throttle position sensor is VERY common on the 4.7l motor causing many symptoms, one of which is a surging, or searching idle.
IIRC there is also a pcm update for some of the wk's, I think it bumps the idle speed up a bit too. You would ultimately have to go to the dealer to have that checked though.
2005 Jeep Grand Cherokee - Gone but not forgotten!