I think the 'diesel' ad SwampYankee refered to was in response to GM's diesel cars that were getting very good reviews at the time and of course cost less than a Mercedes.

About three years later the problems with GM's converted gas engines began to show up and they were gone. Peaguot was still selling them and VW had the diesel Rabbit; even Nissan had a Maxima out with one and then so did Volvo.

But when was the last time you saw one of those?