Originally Posted by b16ahybrid

I commend you on doing your homework and knowing the basics...
It does sound as though your engine is running excessivly rich. Lower egt's could be because of an excessive rich condition and a loss of power is an indication. Sounds like you check your plugs often, so I would lean towards possibly the 02 sensor giving up.. Although it should throw a code, your afr and agt's would be all aout of whack with a bad 02.