I have 2008 Jeep Grand Cherokee 5.7L and I noticed a couple days ago that while on the freeway going around 65-70, I would let off the gas and my rpms would drop to around 1200 and the needle would just be bouncing/fluctuating up and down from 1200-1800 rpms. It only does it when I'm on the freeway going over 60-65 mph and let off the gas and coast. I also noticed this only happens when I have the A/C on too. As soon as I turn the A/C off it would stop doing it. Just wanted to see if anyone has come across something like this before I take it to the shop. I hope I'm summiting this in the right thread, if not I apologize and thanks.