Okay here is the present problem with my 1976 242DL with CIS:

The car fires up strongly, and right when the rev's settle down the engine shudders and almost stalls, or stalls if the headlamps are on. When I detach a vacuum hose for the EGR system from the intake manifold, the revs go higher and even out. This happens when the engine is cold and warm. The engine runs fine when driving, only when idling does it stall.

Some items to mention:

It has always had a loping idle. There has always been an audible whining from the fuel pump (is that normal?). The timing belt hasn't been changed in over 50,000 miles (I'm on it, I swear).

So could this be a fuel injector seal leak? Or a vacuum leak? or an auxiliary air valve problem? Cold start injector? Air mass sensor might be a bit dirty... Or a fuel filter? I replaced the fuel filter last year... Or could it be the thermo time switch? Or coolant temp sensor?

Your comments are greatly appreciated!!