Ridding with my buddy to lunch the other day, the vehicle started shaking like you would get with a misfire. We came to a complete stop at a redlight and he shut off the grand Cherokee and cranked it right back up and everything was fine. It has only happened just a few times but now he says its becoming more frequent and doesn't want it to be a transmission problem that is causing more damage. Someone told him that it sounds like a trans issue, but the only thing I can see causing that is the converter staying locked....but the vehicle doesn't die.

Any suggestions? I have no clue about jeeps.... its a 2001 Grand Cherokee.