I have an 06 Ram 1500 and having pretty much the same problem, 6,700 miles.When I take off there is avibration and a grinding sound also. Mine does the jerking and a grinding sound also when it trys to drop down to 4 cylinders with the MDS. There is also that little slip when it shifts into 2nd and 3rd gear and vibration. Dealership said it was the muffler, been in shop 6 times now and finally got the hole exhaust system and pipe replaced. Like I figured, that wasn't it, it is till doing it very badly when it goes from 8 to 4 cylinders. I still love the vehicle, one of the best handling trucks I have ever owned. Thinking of trying to get a new one out of this, don't know yet. Purchased in Sept. and as I said, 6,700 miles, and 33,000 dollars, it shouldn't have already been in the shop 6 times! SOON TO BE 7!

 

if it keeps failing over and over wouldnt it be cheaper in the long run to put in a better converter?

 

The last time I was in the shop for some "odds and ends parts" There was a 2005, 2500 Ram (Hemi) that had a bad Accelorator pedal sensor. It was causing poor mileage for the owner. I bet a bad sensor like this could cause a hesitation, since it is similar to a TPS, and when a TPS has an "open spot" in it, itcancause a hesitation. Just my $.02