my tachometer seems to have stopped working right it twitches all the time even when the car is off and only goes up wont read the actual rpm at all. im thinking its a grounding problem can anybody lead me in the right direction ill post a video if need be tomorrow

 

Nobody?

 

I've never experienced this myself but here are a few things that you could look at. Check out these two threads:

https://www.audiforums.com/forum/b5-...t-tach-166656/
https://www.audiforums.com/forum/aud...problem-28855/

And here is a really good reference for the gauge clusters and the wires going to it:

Understanding differences between Audi A4 clusters and the compatibility issues

I would use the last link to find what color your tach wire is and what connector it is in. Then unplug the connector from the gauge cluster, turn on the car, and use a meter to see if you're getting anything on the tach wire. That should tell you if it's the gauge cluster or something else. In case you don't know how, here's a video on how to remove the gauge cluster:

Instrument cluster removal - Audi A4 S4 A6 - YouTube