The ecu is smart enough to know that you unplugged the MAF. I can do nothing but unplug it, and plug it right back in, and 70% of the time it will set a code. Earlier years don't seem to be as sensitive. As far as your pcv, as long as you hear an audible "click", it should be tight. Your tube/filter combination should be one of the most trouble free set ups out there. If codes come back, I would check your clamps, they need to be TIGHT. Way tighter than you would think. The car will throw a code for lean, but it has to be pretty bad to do it, as it can compensate quite a bit. Open loop is a complex strategy on this PCM as
wookwook has alluded too.