the 2 above posts are the same as my problem was
but now no problem at all for me car drives so much better now, as i thought it was just first i was struggling with but after changing the linkage all the gears are so much smoother now
the problems you guys are getting with first is because the gear selector is attached to a rubber block and round that is a metal clasp that wears away so when you are changing gear the selector has not gone back to where it should of due to excessive wear
the only other problem really is the adjustment which again is fairly simpleon the other cable going to the gear box it is attached to a bolt on a slide, make sure the adjustment is somewhere in the middle, as thats where both of mine were, bang in the middle, so like i said now i have no problems at all
if you need help changing the linkage just ask as there are lots of people on here who will give aid as its a common problem with the mk3