Check your fuel trims STFT and LTFT, then see what your AFR is like when idling. Your trims might be a little to out from the cold weather and you need a MAF calibration.
If you MAF isn't calibrated at least within + or - 10% you are going to run into issues.
(I personally try to get mine as close to 0% but it's impossible, as with temperature change the targets moves)
And if its not that it could be a clogged intake/dirty filter. Not sure what else...