I've got a 67 250SL with the mechanical fuel injector pump; I'm having ongoing difficulty once it warms up. Still runs, but seems to be choking on too much air. My mechanic says that I need a new "cold start speed valve", but cannot seem to locate a new or used part that will suffice. He indicates that the next option is the very expensive (yet once-in-a-lifetime) injector pump rebuild. Does anyone know how to find one of these valves? I had a look in my "Star Quality" parts catalog, but the cold start valve they show is nowhere near the injector pump.

Any comments or ideas?

Richard