Sometimes (one every 10 starts) when I backup to pull out of my parking spot the car starts to shake pretty violently. Even when I put the car into park during the shaking it still does, but when I put it in drive it rides fine. Any Ideas? Its an 04 3.0 Auto. My guess either the brakes are sticky or something is wrong with the tranny.

 

get the ecu scanned for fault codes. autozone should do it for free. post any codes up and we'll try to help.

 

Does it seem like the engine is almost stalling? I don't know why it would be brakes or tranny if it does it in park too. If your idle is set too low, the engine could be sputtering which can make it shake a bit. Bad engine mount would make it even worse, but they should be ok in an 04.