91 740 Turbo - Out of the blue I start it up and it idles like it is running on 3 cylinders. This is a constant miss all throughout the rpm range.

Main fuel pump, relay and filter are new, I can hear the in-tank pump running. Fuel pressure regulator has vacuum with a dry hose. No black smoke is present.

We have good spark at all cylinders, noid lights tell me all injectors are firing or at least are getting power.

What is interesting is that the car will not start or run with the wire to injector 3 or 4 disconnected. With the wire on injectors 1 or 2 disconnected, there is no change in the way the car runs.

I'm thinking maybe a bad injector(s)or plug(s)but I am interested in other opinions before digging into it.

Suggestions are solicited and welcomed!

Thanks in advance,
Curt