Does it feel like the transmission isn't catching the reverse gear?
I have this problem too... sometimes when I push the gas, it feels as though it's barely in reverse (if that makes any sense), and then when I push on the gas (some more), it will catch and jolt the car. Does it feel like your problem is trans related?
I got an answer to this a little while back. Don't recall what it was though... I'm sorry,,,,
Do a search! You'll find the info. Also, it doesn't seem to be any sort of major problem.