VSS jumps around when driving faster than 105..110km/h
 

Hi,
I have this kind of problem with mpguino, that speed and distance reading are giving false readings when speed is 105km/h or more. Sometimes it jumps to 150km/h, next moment it can show that speed is 0....these are extreme examples, but +-20km/h can happen quite often.

MPGuino is installed on Audi A4, VSS is taken behind instrument cluster. Any idea? Does others have similar problems. My previous car had similar problems sometimes. Normally I dont drive faster than 100km/h but sometimes I get false readings around 90+ km/h. Next moment it shows correct values again. resistors in VSS pin are 50K

Update. I have soldered 0.1uF capacitor between ground pin and VSS pin and speed seems to be really accurate and does not jump around at all. after calibration/correction it is off 0.1km in distance of 102km...not bad.
Still needs some more test drives, if accuracy stays like this but as I said - instant speed does not jump around anymore.