Yes, the gauge is useless on steep grades because it's a big flat bottomed tank and the fuel flows to the ends, especially when partially full.

 Early in my life with my '84 I attempted to circumnavigate Mt. Rainier on about 3/4 tank, and as I got into the steep grades the level dropped so fast I couldn’t take the stress for more than a few miles and turned around.  Downhill I had over 3/4 tank!  I hadn't reset the odo and didn't know what was going on so I aborted the trip.  I know now I could have easily made it all the way around, and back then there was even a gas station at the Sunrise visitor center I didn't know about.

Knowledge is power!

Stuart

Don Hanson wrote:

....So I keep an eye on my odo...my gas gauge is rather vague depending on the attitude of the van....