I own a 2000 Cadi Deville. Bought it in 2003 with 53,000 miles; never had serious problems other than coil pack replacement ($150 used part), crank shaft positioning sensor, camshaft positioning sensor, mass air flow sensor, and the usual oil changes and tune ups, but never done at the dealership.
Mine didn't get the vibration until I decided to follow the young crowd and put 22 inch rims on it; then the vibration started, put the stock tires back on and the problem persists. Oh well, that's the price we pay to ride Cadillac.
Time to buy a new model and sell this beauty for $3,000 because we lose so much value so fast...
Awesome car, no complaints, all wear and tear on this beauty. Sensors are the only issue with this big body beauty.
Do you still have the Cadillac?