low o2 voltage

[WhipmastaFlex]

so my car suddenly started to bog and run itself lean today. stock fuel system. i have a digital o2 voltage gauge (see gallery for picture). my car, at WOT, usually runs between .97v-1.05v at WOT. today it was running around .90v-.94v... even lower later at night. car felt like it was pulling assloads of timing, since it barely accelerated... but spooled fully (12psi). later that nite, after i drained the tank thinking it was bad gas, refilling it and still having the same problem, my car didn't want to start. takes a few clicks before it turns over. battery voltage on my TT shows between 10.9v-11.5v. then i notice my water temp gauge dancing around as i barely depress the throttle. my water temp was ungodly high. however, no smoke from under the hood or exhaust. car idles fine, normal vaccum, and drives fine while not in WOT. no CEL. nothing happened to my car while driving that suddenly altered performance.

so could it be: bad fuel pump/fuel delivery --- headgasket --- electrical malfunction --- fuel filter (15k miles old) --- something else

thanks

 

[WhipmastaFlex]

well i started the car this morning and let it idle for maybe 3 minutes. the coolant was already so hot it was smoking, and the top half of the thermostat housing was red hot, but the bottom section of the thermo housing was cool. the radiator was also hot, after only 3 minutes of idling. would that be a bad thermo housing or water pump? the water pump was replaced 25k miles ago.

 

[WhipmastaFlex]

changed the thermostat. coolant is smoking hot, radiator is cool. doesn't look like it's moving water. i guess it's the water pump. :thumbdown