As the topic says, "what did I do now?"

My 8 was having issues with the SSV and air pump (code P2259 and P0661, I believe), so I took it apart to replace those solenoids and the SSV (it was really, really nasty and stuck open). I followed Jon 316's guide on the SSV replacement, and while I was at it I cleared a blockage in my heater core, replaced my radiator fans, and reinstalled the Sohn adapter that was removed when my engine was rebuilt a few months back.

After putting it all back together with no extra parts and nothing seemingly out of place, everything looked good. I topped off the coolant that had drained, fired her up, and things seemed to be going pretty well for a few minutes. A bit of white smoke from the tailpipe from the Seafoam that was used to clean the SSV port and a bit of spilled coolant cooking on the radiator, but nothing unusual.

Then she started bogging down. Dropping down to around 250 RPM and then bouncing back up to ~2,000 (it was a cold start, after all). The P0138 (high voltage on the rear O2 sensor) was thrown. I inspected everything I could, and nothing looked out of place.

I took it for a quick drive around the block and the power was really low below 4,500 RPM. It seemed to do better above 4,500 RPM. Another code was thrown. I don't remember the exact code, but it was for running rich. After turning it off, the EGI relay was clicking quite a bit and quite rapidly. I unplugged it for now.

So what did I do? Nothing seems to be out of place from what I can see. It sounds like I screwed up some electrical connection, but I not sure which or how.

Info on the car: 2005 RX-8, M/T, 158k miles, engine rebuilt ~3k miles ago. All recalls completed save for the recent airbag one.

=== UPDATE ===

I cleaned the connectors on the PCM that were removed during the SSV replacement suspecting that water got in them when I was flushing the coolant (it got a little bit... messy when a hose came lose during the flush). After doing so, the car runs fine. I was hoping that all the problems were gone, but I'm still getting the P0138 code and now I'm getting P0113, high voltage on the air intake temperature sensor circuit. Still runs just fine. The battery light was also coming on occasionally.

Weird junk.

=== UPDATE 2 ===

In the event anyone else stumbles upon this, I took every connecter that I had messed with apart, cleaned each one, dried them extensively, and plugged them back in. Mystery solved. It works fine. Mods, you can lock this if you want.