I have two '92 300D 2.5 Turbo's - one with 197k miles and the other with only 92k miles.

Both are new to me (few months) and it seems clear to me that the turbo is not working on the 197k car. The engine revs up and you never feel that "pull" you get when the turbo kicks in (like I feel in the 92k car).

What are the basic things I should check?

Thanks,

-John