Other factors are air filter, shut off valve, clogged exhaust, tank filter, waste gate open, manifold pressure not getting to the alda.

Changing the filters should do it.

__________________

Present
1987 300SDL
1991 300SL
1990 560SEL
2001 ML320

Past
1969 200D 1979-82
1983 300SD 1984-85
1972 250C 1982-02
1995 S350 2011
1997 S320 2012