Thanks for the knowledge. I just checked the plenum air flap. Yes it depresses easily and smoothly, and returns to the closed position in a gentle, but definite manner. I had my wife crank the engine so I could watch the flap. Nothing happened on cranking. But when I manually depressed it, as she was cranking, fuel flowed to the injectors (I had one injector line disconnected so I could monitor fuel flow). So fuel doesn't seem to be the problem (although I did not check to make sure the injectors were letting fuel through).

But - I noticed that the engine is cranking unusually slowly. The battery is fully charged and known to be good (it tested as "good" also on a load tester). But the engine doesn't turn very quickly at all on cranking. So now I'm wondering if that could be my problem. And if so, what would cause that? A failing starter maybe?

-Brett