My tachometer goes crazy every time I drive now. The tach will be normal for a little while then it will either go straight to 9000rpm (when I'm really at 2500-3000rpm) and jump up and down, or it will raise to about 2000rpm above my actual rpms. Can anyone help me with this?

 

Bad fuse? I'd also check the alt. and battery. The electrical system can play weird tricks on you sometimes. I wish I knew more about it, but here are some basic rules for electricity:

1. You can't see it.
2. It'll hurt you.

There, that's all my knowledge, do with it as you will.

 

I had the same problem, the tacho itself ended up being stuffed.
Mine wouldn't do anything and suddenly it would spring into action. And other times it would just slowly creep up or it would just sit on 9000.

I couldn't find areplacement IC for the one it had on it so I had to replace the tacho. Found one a whole cluster set on ebay and just swapped out the tacho.
Everything works fine now

You could try taking it to a instrument specialist but chances are its stuffed.

 

Not my write-up but this is likely your problem. It's common, and inexpensive to fix:
------>http://www.umsl.edu/~tch9gd/Tach.pdf

 

Thanks for your replies, I'll let you know how it comes out.