With the car in 1st gear, you standing in front, how much can you all "rock" or push your car back and forth? I expect there to be some kind of movement, but I was waxing mine yesterday and noticed she will move a good half foot or so. Is this normal? It always feels like I have slop in my drivetrain, is this indicative of something?

ahh yea the clutch could have something to do with his problem, an unadjusted clutch say after a few miles could result in a loose clutch. therefore he might not notice goin down the road, but maybe not enough to hold full pressure when not running. i know it sounds silly, but they put a park brake on vehicles for reason, you cant always rely on the inner workings of the drive line to stop the vehicle from moving while not in opperation