When I fill my 99 Ranger Sport, the fuel gauge takes about 10 minutes to "catch up" and register full. Any thoughts?

 

There will be a Slosh Module(electronic circuit) in the dash that prevents the Fuel needle from flopping around when driving around corners, as the gas sloshes from side to side and forward and back.

It could be going out, it is suppose to slow needle movement down, but seems a bit excessive in your case.

Not sure on the '99 but it was a circuit board that could be changed on earlier years, you of course have to pull out the dash to get to it.

Google: Ford ranger slosh module