Heres my problem, it fine at idle, but as soon as it goes past 3000 it jumps all arround, even goes up to 5 and 6000. but as soon as I stay right arround 2800 and 3000 its fine again...
Oh BTW it is a factory tach



87 B2

 

I have the exact same problem on my 89 BII. Sure would be interested in the fix when you figure it out.

Bill

 

Well I replaced the Ignition coil, and it did it for about an hour or so of driving, then it all stoped. A week later its still working fine... Will keep posted. It may have been a bad ground connection at the coil.