I spent a lovely few hours at the mechanic's shop again this morning. The car was "fixed" Thursday, but when I picked it up, the service engine light came back on. The shop was closed by then, and I didn't have a ride, so I had no choice but drive it home. Yesterday and today, the service engine came on 3 out of 4 times that I'd start it. It was on for the entire trip from my house to the mechanic this morning... but, of course, it didn't come on again when the mechanics started it up.
The car needs more work... but I don't know if it's worth it. I've probably kept the thing on life support for too long anyway. I'm kinda stuck -- I've spent so much repairing this car that I don't have too much to put into buying a new one. So I keep pushing it a little further -- $400 here, $150 there... hoping that it will run long enough for me to get ahead. It's a losing battle.