Flashing Check Engine light

["Tom Borden" <teborden2@xxxxxxxxxxx>]

Have a 1988 528e with 136,000 on it.  The Check Engine light on the dash
starts flashing once I'm underway, sometimes within 30 seconds, other times
longer.  It does not seem to be event-driven.

I press the overhead console button to clear and the light goes out and
usually does not reappear during the trip, though sometimes it does.

It's a steady flash, not a long-short code.  Recently I had to replace the
middle of three relays attached to the side of the engine fuse box and am
wondering... could it be one of the other two relays?

Don't know if it is related, but only other abnormality to consider is that my
O2 Sensor light went on a month ago, a day after I dropped the rear half of my
muffler.  Replaced muffler... does anyone know if O2 Sensor merely needs to be
reset?  It's aftermarket and was installed at 96,000.

Beam-on.

Tom Borden
teborden2@domain.elided

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