Mine did this on me old RT, I fixed it and all was well.
To fix it all I did was remove the rev counter from the instrument display, I may have had to remove the plastic front (it was ages ago), I did regret removing the plastic as it looks dodgy if any future owners ever take it out to replace bulbs... its glued on at factory... you might be able to remove counter.. anyway...
When I moved the needle it was free as anything, strange I thought..
You have to note the EXACT postion of the needle at rest.. then using a flat screwdriver, I carefully removed needle by putting the screwdriver under the central circular part of the needle. Then I replaced it back on with a snap, at the exact same position... it may sound a little odd or far fetched but give it a try.. mine worked fine after that. It stuck at random positions when I first got car but was for as long as I had the car after that.. 4 years in all.