This is a common problem with these cars and is caused by the gauge needles sticking to the stop pins , when it happens slap the top of the instrument pod and if the needles pop up that's your problem.
The solution is to remove and dismantle the instrument cluster ,then clean the needles and stop pins with spirit or slip fine tubing over the stop pins.
This link will show you how;http://64.233.179.104/translate_c?hl=en&u=http://www.mb-treff.de/tipps-tricks/w202/tachozeiger-klebt-fest/index.php&prev=/search%3Fq%3Dhttp://www.motor-talk.de/f73/s/%26hl%3Den%26lr%3D%26sa%3DG
Make sure you disconnect your battery before starting or you will activate the SRS light ,which will have to be reset by a dealer or auto electrician.
George.