Hey guys! My gas tank read "254" (till empty) when I got into my truck, but jumped down to 203 after a short 10 minute drive. When I got back in, I watched the number tick down quickly, before stopping at 195 and then returning to ticking down 1/mile. My truck is still on it's first tank so I think it might just be a calibrating thing but I just wanna make sure it's normal and not something I need to go get checked out soon.

 

This is not unusual especially with a new truck. Things like parking on a slight incline will give the sending unit a false reading and it will adjust accordingly as you drive. For some reason this design is very sensitive
I would do your own check with miles driven and gallons used when you fill up next.