CEL comes on and off...

[mazzo]

Lamba code - 1222.
I start to think maybe it's connection issue somewhere - that when the engine bay is getting hot, some connection start getting loose...

[moatilliatta]

Replace all your relays.

I've seen bad voltage to the Oxygen sensor cause sporadic flashing of Check engine Light.

[mazzo]

Ok, let me do that this weekend. Will see if that helps :)

[mazzo]

So looks like the issue is related to the relay, but not on the relay itself - it's the wire connection that goes under the socket for the relay. I check and secured the connection and so far have not see any CEL after driving for 30 mins. I hope that reminds the same.
This reminds me that a lot of time the issue is not at the components or parts themselves but rather the wiring is having issue. They are over 30 years old, afterall...