My speedometer just started to act up on my 94 Chevy C1500.
Manual trans, pcm:16197427
Datalogging with Tunerpro shows the same fluctuating readings that the dash speedometer does.
Started acting up in the 50 mph range, but now does not want to read anything until about 15mph, then fluctuates at times.
Checked wiring, and grounds and have not found anything wrong, getting no error codes.
Does this sound like a bad vss, is there a way to test a vss?
Hate to just throw money at it and hope, so would like to know more.

Thanks, any help and insight is appreciated.
Been searching net, haven't found much yet, my Haynes manual says take to dealer to diagnose. That's not going to happen