Fuel gauge sticking.

[Mike Hamm]

I've noticed lately that when filling the truck's diesel tank the fuel gauge will stick for awhile and then suddenly jump up to catch up. Today, when the nozzle clicked off to indicate the tank was full, the indication still showed 1/8 tank to go. I went ahead and paid and left and as I drove the needle finally worked its way to the full indication. First time it really stuck and took awhile to finally indicate. 

This is on my 2016 GMC 2500HD Sierra Denali 4x4. Diesel, as mentioned. The fuel gauge is one of those graphics generated gauges, not a mechanical one on the dash. 
Anyway, any thoughts on this? It used to go up so smoothly now it seems the sticking is getting worse over the last year or less. 

Is there something I can add to the fuel tank that might help clean the sensor and get that indication back to smooth flowing again? 

Thanks for any help.

Edited September 1, 2022 by Mike Hamm