[339A]

Just flew from GLD to MKO today, and on the way my 496 started to give erratic readings on the Altitude... Everything else was right on and seemed to be functioning normally. We were cruising along at 7500 feet and had flown from FTG to GLD with no problems. We were about an hour into the flight from GLD to MKO when we started having altitude swings of several 100 to a thousand feet or more!
I turned on a backup Lowrance Map that I have just to see if the government was messin with the satellites. It was reading right on with only typical varitions.
I tried several things like disabling the WAAS, clearing out the track memory, etc., but nothing made any difference. Has anyone else experienced this? If so, please let me know what you found. I really love my 496 and hope this is not an indication of some kind of failure.

 

[N941WR]

You might need to rest the 496. Check out this tread on how to do that.

 

[zilik]

We were cruising along at 7500 feet and had flown from FTG to GLD with no problems. We were about an hour into the flight from GLD to MKO when we started having altitude swings of several 100 to a thousand feet or more!

Glad to here you made it safe and sound. You probably arrived MKO several hours before we got back to FTG. Did you notice how many satellites the garmin was using? I have seen my 396 drop to 3 sats and elevation suffers when this happens but never with wild swings in altitude. If everything else looked normal I would bet nothing is wrong. A call to Garmin may clarify things.