I tested it when I had the plenum off. It met the specs, and I didn't change it. I don't know why it would be a problem now. I won't entirely rule it out, though, if I can't figure this out.

I tried to find a sensor that I forgot to plug in. Haven't found any yet. Same with vacuum hoses.

I'm wondering if I should keep playing with the coolant system to see if I possibly didn't get all the air out. Before I fired it up I got the radiator full and left the cap off. Big mistake! It blew coolant everywhere. So, I capped it.

For some reason I can't remember how I did it in times past. I think I've always tried to leave the cap off if I could. I don't know if that makes a difference or not, but once again, I didn't see any bubbles coming out of the T-fitting when I cracked it open.

I wonder if there's something significant about the fact that the O2 sensor goes into closed loop only when I give it some throttle?