Well....it's alive!!! Installed the new CTS as soon as I got home, and fired her up. Right away she sounded better, as it wasn't choking on fuel anymore. I let her run until the t-stat opened and the engine warmed up. It restarted 3 times, which was enough assurance to go for a ride. 5 miles with no issues...except the brakes, but I'll tackle those once I get it to the shop with me on Thursday.
I now have an understanding of this thing. Thank you guys for the help. The SES light is off, and she runs good. I'm definitely happy I saved it from the crusher, because that's where it was going if I didn't take it from the father-in-law.