Well, now it's throwing two codes. The MAF code, and an EST wire code. Apparently it's grounding out somewhere....I'm going to look at the MAF heating relay, and make sure all the wiring in that is good, since it (visually) looks to be a bit jury-rigged...and I'm going to see if I can't find where the EST wire is grounding out. Also need to replace the set screws on the throttle positioning sensor....which is likely also part of the problem. Once these three minor things are out of the way, I'll see if she's running any better. Should be fixed by the end of the week. If these take care of it, great...if not, back to looking at the ECM...and also the fuel pressure. I still think it might have something to do with the fuel pump or O2 sensor, the way the car is consuming gas...Starting to look like I may have a lot of little problems, instead of one or two big ones.
(Forgive me if I've screwed up any terms....electrical is something I don't do, so I'm relying heavily on my mechanic for info right now.)
Oh, and I've done a vacuum leak check...well, the poor man's version of one, anyway.
Nothing showed up.