Hi there,
It sounds like it's running way too lean, and the thing that comes to mind is a possible shorted temp sensor or wiring. The temp sensor should have a high resistance cold, going towards lower resistance hot. I'm not familiar with your engine, but this is the way most all systems work.

__________________
Richard Wooldridge
'01 ML320
'82 300D 4.3L V6/T700R4 conversion
'82 380SL, '86 560SL engine/trans. installed
'79 450SL, digital servo update
'75 280C