I have a 2006 3.0L Volvo Penta with a Faria gauge. Has approx. 67 run time hours on it. This year - first time running it, when I trim up and it gets to about 1/4 the gauge suddenly jumps up to the top and stays there. When I hit the trim down, the gauge will bounce up and down and then finally settle to normal (1/4 and below). I checked the wiring attached to the gauge which is all fine. Is this a sender unit problem and if so is it an easy fix? If not what other issues could it be? By the way - the stern drive is trimming otherwise properly.