2002 Acura RSX Low Idle at cold start

My engine light has been coming on intermittently for the last 8 or so months. Recently on a very cold morning, I went out to start my car and it idled very low and stalled out. I took my wife’s car and left it alone. The next day it wouldn’t start. Thinking it was my battery, I jumped it with my wife’s car. After many fruitless tries, it turned over and ran at normal idle, even though the engine was still cold. About two weeks later on another very cold morning, it started, ran at low idle but did not stall. I sat there until it warmed up and idled to normal RPM. This continues to happen. Not all the time but more commonly when it’s really cold outside. It will idle near zero on cold start but return to normal after it engine warms. This RSX is the type s model which as far as I know has no in-line fuel filter, no MAF, and no EGR valve. Could this be an O2 sensor problem? I recently changed the PCV valve but problems started before then.