Hello again,

Recap: Engine missing on four cylinders. Replaced plugs,wires,cap,rotor & trigger points. Compression, dwell & timing all good.

Update: While idling: (1) Fuel pressure only 18psi -turning adjustment screw on fuel regulator has no effect. (2) Mixture adjustment screw on ECU - turning it through entire range has no effect on engine. (3) Low vacuum - 19Hgi @ distributor vacuum advance, 10Hgi @ door lock vacuum line, 5Hgi @ MAP sensor.

I hope this info can enable those more experienced than I to point me in the right direction. Thanks -Mike

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1973 280SEL 4.5