Stop in for a cup of coffee

Fury runs the same, fine when you go fast but shudders cruising at parkway speeds. I've been more worried about water leaking in when it rains, I just finished replacing the two door seals that were missing, with some universal kind a FCBO member recommended, it is about to rain today so we'll see... Thanks for asking.

Could it be something worn in the front end??? U-joint???

If it comes in at one speed and goes out at another, then it is harmonic - which is usually a balance issue or loose/worn component...

Try to determine what engine or road speed it kicks in and goes away... Does it happen in all gears at that RPM, or just hi gear???