Idle problem after battery change

I changed the battery in my highly maintained 94 Lumina 3.1 after I
noticed that it was cranking slow on cold days. It had been running perfect
with a rock solid 800 rpm idle.
I had to remove the air box and connector to the airbox hose to get the
battery out. Now that I have this simple task done, I start it up and the idle
bounces from 500- 1000 rpm over and over again. I figure the ecm needs to
relearn things so I drive it 5 miles. No luck. The idle is steady at one stop
and eratic to the point of stalling at the next. I checked all vacuum lines.
Nothing out of place. I remove the airbox hose to check for cracks. It looks
good. By this time it is dark and I haven't looked at it further. Today I will
paper clip the aldl and look for set codes and reset the ECM. Does anyone have
any ideas on what is going on here? I keep thinking IAC valve but that is just
a wild guess and what does that have to do with changing the battery? I will
also add that I cleaned and lightly greased the connectors. I don't get a check
engine light. Thanks for any input.