Date registered: Dec 2013
Vehicle: 1973 280sel 4.5
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Yes. Here is the full sequence of problems/resolutions.
Hard to start, missing at idle and running very rich at idle. Idle screw and adjustment on ecu had no effect. Ran okay off idle, but still seemed a little rich (observed black smoke out of tailpipe).
Checked fuel pressure and it was pegged at 90 psi. Discovered blocked return line from regulator. With pressure at 30 psi car would not run at all. Cranked pressure up to 50-60 psi and it ran, poorly, as through it were starving for fuel.
Sprayed ether around intake and discovered several vacuum leaks (the seals between the upper and lower intake were badly cracked).
Pulled the intake and replaced the seals and gaskets. Still wouldn't run without forcing it to run rich (disconnecting temp sensors and cranking up fuel pressure).
Tested injectors -- flow rate and spray pattern was suspect. Perhaps the ravages of time and high pressure damaged them? $700 later (thanks worldpac same day delivery) and it was running like a top. So there were several issues to unravel, but new injectors were, indeed, the final piece.