Atleast once a week the eng can be,is hot and cold. The vehicle moves ever so slightly, a quick bang-jerk and than its over. I had it to my dealer,look at it they did notfind anything worng. it happens when I turn the key on, I feel this jolt through the transmission. The vehicle is in park, on the level and in my garage. The jerky-jolty movement has happened when the i crank eng and as soon as the eng starts up just for a mili second.