le sigh...
Disconnected the MAF sensor... no change (it actually made it worse. I think this is supposed to be normal). Ran the motor @ 3,000 rpm and disconnected the electrical connection going to each injector one at a time. #2-5 caused the engine to stumble until it was reconnected, which is normal. #1 and #6 produced no change in the performance of the engine. They are either not getting a signal or they are not getting fuel, or that cylinder is not getting a spark (left my wire tester at home -- I did this at WalMart). Also, taking off the oil filler cap causes the engine to stumble and die as well (I think it's supposed to do this).
None of this explains why it only acts this way while the engine is warm.