Might be a dumb question but I can’t find an answer with searching. I have an afr gauge so monitoring this is easy, but it’s also noticeable because the cat starts stinking. Whenever I’m climbing a hill and I’m above 3k rpm in 4th or 5th gear my motor runs completely rich with anything other than very slight throttle input. Is this normal? It’s smog season for me here in California so I swapped in a new denso o2 sensor (pretty sure the one that was in there was stock) and since I’ve noticed this happens more often. Before it would only be on steep hills where I have to give it the beans to keep moving with traffic and now it’s pretty much any incline. Started the day after I unplugged my battery for a couple hours and swapped in a new cat and o2 sensor. Anyone else have this happen? Is it normal?

1990 22re 4wd 4runner