Quad Driver B is a fun one. Problem with the pcm'* of your generation IMO is that they weren't specific enough. Yet they were better than their predecessors.
Having 4 things to look at gives you a starting point. Check each of the other items. TCC you can check by driving and gently touching the brake pedal over 45mph to see if the TCC disengages and reengages shortly afterward. The EVAP soleniod you need to have the car up to temp and running for X amount of time (sorry I forget the correct length) , then the evap will buzz/actuate for a moment. The BCS will usually work 100% properly and give no symptoms of being bad.
This happened to me, when I owned a 95. No symptoms, I shotgunned a BCS and fixed the issue. I do suggest testing all the other items first though.
00 Regal GS: All kinds of cool stuff.