Nice low miles. Congratulations!
Perhaps you don’t know this, but there is a set screw with machined tip (cylindrical), smaller diameter than its threads. The head end of the set screw points towards the front of the car. The cylindrical tip of the screw fits into a perfectly sized hole in the shifter shaft and perfectly locates the knob. If the set screw loosens, the knob will be loose but the knob won’t come off the shaft until the screw is loosened enough that the cylindrical tip clears the locating hole in the shaft.
Could it be that the knob is fine, and you just need to tighten the screw? I forget if the screw head accepts an Allen wrench or torx bit - sorry - I used to know which and the size. Put your parking brake on (chock wheels if needed), turn the key to the run position (engine off), and pull the shifter back to the ‘L’ or autostick position (depending on if your car has autostick or not) to make room for the tool to tighten the screw. A flashlight helps find the screw and insert the tool.
If that is your problem, that is your zero-cost solution.
EDIT: I just did a search. Shift knob screw is torx 15.
'98 LXi - Later Concorde gages (black w/ chrome rings)/'99 LX - LHS gages (white) - HIR bulbs
Last edited by peva; 10-04-2019 at 08:05 PM.