Right off the bat, I'm going to say check the grounds going to your panel and to the gauge/perfect pass itself. If it's just shutting off completely, it could very well be a ground issue. A lot of the times, builders will put a small gauged lead over there and have that branch off or daisy chained to feed everything and overloading it. Perfect pass is very sensitive to having proper voltage and a good ground is the basis of that.
Otherwise, if it's not GPS speedo, check the pickup. You may have to clean it out if something is clogging it up.