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535i Fuel Injection questions?

I have some questions about my 1985 535i. My 535i has 104,000 miles on it,
and has recently had the following service: valve adjustment, new 02
sensor, full inspection II service, fuel injector cleaning (fuel additive).
Despite this, it has the following problems. Rough idle, surging under
acceleration (comes and goes), much better performance when the engine is
cold. It also seems that the low RPM performance is sometimes rough. I
have asked both my mechanic, and the dealership about these problems. They
say the rough idle is normal, and that they didn't notice any surging or
loss of power after the engine was warmed up. I'm inclined to think that
I may have one or more fuel injectors that are clogged or dying, but I
don't want to replace them if that's not the problem. I'm also concerned
that the Motronic system is confused, especially since my mechanic said
that he found it was running lean (with the O2 sensor disconnected), and
so adjusted the airflow meter. From my understanding of feedback control
systems, that does not strike me as the right way to solve the problem.
Any help on this would be greatly appreciated.

Thanks,
Nat Crutcher

1985  535i, 104K mi.