The later 124's had vacuum operated waste gates on the turbo. If you lost vacuum (bad booster, bad vac pump, etc) that would explain ALL of the problems except for the door (you should have an electric vacuum pump for door locks).

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)