bad motor/trans mounts could cause that, also may be that the idle is too high. It can be idle smooth but still high if the O2 sensors or mass air flow are not reading properly. somtimes just driving a bit can help if the stuff is just dusty/dirty.
EDIT: when the mounts dry up there will be play in bolts allowing the motor to rock side to side when you shift. (I don't recommend it but I have just tightened the bolts down to buy some time and reduce stress on the mount themselves but it can make the rubber decide to quit out entirely)
Last edited by TerenceandMary; 03/22/2021 12:25 AM.
