Manual Transmission Shifter Movement or Vibration

I have a 99.5 Jetta with a manual transmission. I have noticed for some time that when I start off in 1st gear the shifter will pulse forward and backward about 1/4". The pulsations increase in frequeny as the rpms increase. Also there is a rattle/vibration in the shifter when in 3rd at certain rpms that will stop if I put my hand on shifter. It shifts fine and there is no noise in the trans.(other than the shifter rattle). Could this be a failing lower engine mount or possibly just needs to have shifter cables adjusted? Thanks in advance for any help on this.

CP

first change your transmission fluid.

check the dieselgeek website for instruction on installing their short shifters to see how to adjust your shifter cables on the tranny end.

get a look at all 3 of your motor mounts (two sides and a dogbone one on the bottom..) see if anything looks funky or they ar emoving too much.

good luck!

any movement in the shifter is too much.