79 runs like crap after top end rebuild
#61
I wouldn't bother with th O2 sensor. Last time I adjusted the A/F on my car was in 2004, and based on the three smog checks since then it's running cleaner with every check, though the differences are minute. I don't think you have to worry about it drifting, unless you didn't clean everything up thoroughly which would account for some change over time.