I neglected to mention that I have no less than two used air mass meters in the trunk, and suspecting that might be at fault (and easy to swap out), I put one of my spares in. I then neglected to plug the AMM back in! Of course I realize this at about 8:55 tonight - put all my heavy clothes/coat/boots/etc. back on, go back out to the parking lot and check - yep, AMM isn't plugged in. Plug in the AMM, car starts with the surging idle but then once running smoothly drives just fine - even gives boost with no backfiring. Turns out I drove all the way home in "limp home mode." I'm thinking maybe it's possible that the AMM that was in the car before the swap may have gone bad and the initial symptoms - rough idle, backfiring, etc. - was the revert to limp home mode that you get with an unplugged or malfuctioning AMM. Still, I have the issue of the mysterious surging idle at start up though. My mechanic/parts guy said a while back that he suspects a bad Idle Air Control Valve for the start up/die/start up fine problem. Now to keep my fingers crossed all night so that the car will start and run okay tomorrow so I can go to work. Anyway, I'm still going to entertain suggestions as to the start-up issue.

Thanks,
Matt