Yes, a solid 1.3v on all four O2s. Occasionally on a cold start it'll try to drop down to a normal fuel level, stutter, and then rise back up to 1.3v. And then stays there wether I'm accelerating or just cruising. Very very odd and confusing. Just threw a P1164 code today as well

 

That code says O2 sensors all the way, but of course it could be wiring. The steady 1.3v says it's running well beyond the range of the sensors, which is rich enough to cause all the power loss, misfiring, and rough idling.

I'd hate to say you need at least 2 new sensors, but from my computer desk that's the best I can do.....and then I have to wonder what could've caused this issue.

 

I kept thinking that was it lately! Took it to the shop today where he can read each wire and possibly find a bad ground? Hopefully he'll get to the bottom of this :/

 

I have an 03 w/ no mods and had the same symptoms as you w/ the p0300 random misfire code. Turned out to be a bad coil for me. Problem started slowly and was intermittent, a year or 2 later it kept getting worse. Kicking myself that I didn't test the coils sooner (disconnect one at a time to see which one made no difference). Hope this helps.

 

FIXED! Here's the follow up: took it into the shop, both front oxygen sensors were reading out of spec. Replaced them, better, but it still did it. Replaced one of my other after-cat oxygen sensors FIXED. All three O2 sensors, AND my maf sensor went bad at the same time!!! Who would've guessed....just happy it's all good now

 

That's good to hear. Hopefully it stays fixed, because something caused those sensors to fail.....And that something was probably the MAF.