Went lean...

Yeah sorry. I tried to be clear, but I'm extra good at assuming everyone can understand what I mean to say.

I just meant the top of the air filter housing. I didn't change anything on the carb. When I got home, I checked to make sure I didn't accidently pull the pcv hose off or the distributor advance vacuum line off. They were still perfectly in place.

Really only a few things can make it read lean. Excess air (vacuum leak), lack of fuel (clogged filter, failing pump, pinched line, etc) or an exhaust leak to throw the reading off, then just a failed sensor.

My question would be where did the breather filter element go that is missing?