This car is a pleasure to drive, however, it has had its share of needed repairs: wheel bearings, belt pulley bearings, radiator, power aerial, water pump etc., but this comes with a high mile daily driver.
The car has a trademark shudder in steering at low rpms and routine brake replacement, but it's still a fast, comfortable car.
We have a problem periodically with no-start issue. Insert key and turn - all the accessories power up but no crank over of engine. Have examined all possibilities including key chip - now have read that maybe it's a security triggered delay. We will be looking into that!
I have had a '91 Buick Regal GS and a '93 Park Avenue when I bought the Riv for myself - then my wife took it for her car. Both other Buicks reached 500,000 kms, neither ever taking a drop of oil (but similar issues as the Riviera is presenting). We also have a mint 1971 Cadillac with 45,000 original miles and a GMC truck. All GMs, but I now also have an '07 Suzuki SX4 (which will fit in the trunk of the Caddie).
Do a search for the procedure to disable the key-chip activated security system to eliminate the delayed starting problem. It involves cutting and/or splicing one or more wires from the ignition switch.
The car will no longer have the anti-theft system, but really, a '97 Riviera is not exactly on the most-stolen list.