Trim Sender / Gauge All over the place
 

Ok so it seems now that I have my new interior in and spent days wetsanding and polishing to make my boat look new, it is now time for it to begin breaking down.......

The problem of the week is my OD trim gauge is all over the place. When I just tap the trim up button, the gauge will move almost 50% of its sweep. Then after running for about 30seconds the gauge will find it's way back to where it should be. If I tap the trim up button again, I get the same behavior. Also when I do a complete down trim, the needle will not sow it as being all the way down until about 30 seconds while under way. While this isn't a huge mechanical issue, it is a giant pain as I can't tell where my drive is. So basically I am having to watch the GPS and trim up until the speed drops off, then trim it back in a bit... Does this sound like a bad gauge or senders? Oh, I have Gaffrig Gauges, if that matters...

If your wiring and grounding all checks out then you need one of these:
Merc part # 805134A4
It will replace the potentiometer inside the sender on the drive.
We are talking about a Bravo, right?

If you have bad wiring from the sender then you will need a new sender.

Sorry I did not post information about the motor/drive. It is a 496 Mag w/Bravo One Drive.