I just got back from mississippi and my 998 started acting up. My depth all of sudden started reading 1500 feet deep when I was in 4 feet of water. The display was just a bunch of colored dots. The 2d display was all blotchy as well. I run the 6.4 original software on this unit. I am heading back in a couple of days so I would to get this issue solved quick. No other equipment was on except for the trolling motor way up in the front of boat and the transducer was angled correctly in the water level. Any one have any suggestions on what could be the culprit. When I got into deeper water it all of a sudden got better. I put some conducting grease on the prongs when I got home last night so maybe that will clean them up ajd give me a better connection with the unit and its plug ins.....