Engine stalls after starting, now sluggish at WOT
 

Yesterday, I was in town, stopped for about 20 minutes and went to leave. It started, but was running like it was going to die, and after a minute it did. Then, after repeated attempts to start, nothing. Turned, but it wouldn't start. Didn't hear the fuel pump, so that was my first guess.
I get it towed home, and today I got a jump (battery ran down from attempted starting) and it started right away. It idles fine, even revs up like normal in park. Went for a test drive around the neighborhood, and it drives OK, but on an empty street, I floored it and it bogged down real bad. Didn't stall.
Repeatedly backing up and flooring it down the empty street, did the same, bogged down but didn't stall.
Cleaned the MAF, IAC, IAT and TPS. Temperature seems normal, PCV valve is good. No coolant leaks, sprayed cleaner around vacuum lines and gasket surfaces but there was no change in idle speed. Same thing, starts and idles fine but bogs down at wot.

Any ideas what it might be?

Edit: may have found it

Just for laughs, I unplugged the MAF and drove up and down the street. Aside from shifting hard into drive and reverse, no bogging down at wot.