p0106 code

This code occurs when manifold pressure sensed by the MAP sensor falls outside of PCM-predicted values.
If the cam/tune was done a while ago, and this just started occurring, it could be an intake leak of some sort, or the MAP sensor itself went belly-up.
If the cam/tune was done very recent, I'd bet on it being a tune issue, given the behavior of when you see it.
Get Stephen (or someone near you) to log your MAP with the car running, and go from there.
On a 2002, if you're idling at more than 62 Kpa, you will throw this code. A big cam can and will do this...in fact mine idles around 65-68 Kpa @ 900 rpm. In EFI Live, table C3003 need to be upped in the low rpm/tps cells to cure this.
Stephen



