As a kid I creamed over every Seville even the 70's models. After owning a variant of every model I can say this the 76-79's and the 92-97's were the universally loved models that got everyone to take a look at Cadillac. Still many people discount the baby lacs and that is a mistake they were not bad cars, looked lovely, but Americans liked bigger body styles. Gm finally got the engines right in 88 - 92 but feeling pressure to use a "modernized" design they rush another engine to market the North Star.
Cadillac then had the same issue in the 90's they had in the 80's with motors. The 4.1 was weak and could not handle heat at all then the North Star while a great design(Lotus/ZR1) it had casting issues that caused premature head gasket failure. Another issue, Lexus, who set a standard that even BMW and BENZ had a hard time matching till the later 90's. While the Cadillac tried to copy their interiors the cars did not hold up over time. The 98-04 were nice designs but for some reason people did not like them.
While not one of my Sevilles I loved my 88 Deville with only 76K on it.
