Please can somebody help

I have a 1994 280E Auto (petrol) estate which suddenly lost a lot of
performance.

1/.    The engine won't idle at all.
2/.    Once started I have to keep it alive with the throttle or the engine
will stall.
3/.    It won't rev above 4000 rpm. If the engiine approaches these revs the
engine begins to stumble and will cut out even while driving.
4/.    There is a strong smell of unburnt fuel at idle, like the fuel
mixture is wrong.

I am thinking the EMU might have defaulted into a "Get Home" mode...If this
is correct can it be reset and how?

Kind Regards

Mark Lilley