Still playin with the ol girl... I've noticed the last couple stops at the gas station, when I open the cap you can hear the release of pressure or vacuum. I don't know which. Just wondering what that's all about. Do I need a new cap? And could it be related to the intermittent lack of power I have? At no time in particular (it happens warm, cold, full tank, half tank, or near empty tank of gas) I'll just lose what little power my 2.3 has to offer. It always comes back within a few (not more than 15) seconds. The only CEL code I have is related to the upstream O2 sensor - don't remember the codes, but I have one for high voltage and one for low voltage. Just haven't gotten around to changing it yet. It never fails to start - in fact, always starts easily, and has never left me sit. Runs pretty great most of the time. Any thoughts?