I took out my sss for the first time in 2 years and put about 75 miles on it. I put 10 gallon in it before I left this morning and that put it at less than half a tank. I noticed about halfway thru the ride my fuel guage was on Full. When I stopped I cycled the key and the fuel gauge kept going past F. It kept going further and further past every key cycle. I disconnected the battery and that didn't help. I finished my errands and went back home.
I am leaning towards the gauge because it will move up and down when I turn the key off.

 

Bro, check out cluster issues a few threads down.

 

I would lean towards the gauge too. Usually a bad sender will cause no reading or an erratic reading.

 

I'd say it's in the cluster. These trucks have quite a few issues with the stepper motors. On my truck my volts gauge has been doing some weird *** stuff for a few months now.

 

Bad cluster I have seen this 100's of times. PM me for more information in getting it repaired.

 

SO thats what happens when you put 50 gallons in a 26 gallon tank??