Thanks, everyone, and here's a little more info.
This was purchased a few months ago from a dbag by a relative who doesn't know much about cars and I tried to help them on the phone etc. While there were a lot of miles, it was masked somehow how bad the engine was, and I didn't catch it. After purchase, the car drove well without any perceivable issues for two months.
I'm swapping one of my cars with them for it and driving it up to them, and I'm taking the Kia to the southwest because I want this car and they want my alternative (long story.) Restitution from the dbag is also another story for another day.
It's a Kia Soul + with the 2.0 engine. Smoke comes out when driving and the tailpipe is coated with oil, which the car can't seem to keep in it for more than a week. And the oil gets ugly black very quickly. Using Lucas oil stabilizer has helped maintain the oil near the proper level over the last four days (two days of commuting 10 miles each way), but the car still can't go above 40 without sputtering, and the effort to do so makes the engine performance worse.
I have a 2005 Honda Pilot that I am currently selling that can tow it, but that means I have to tow the replacement car from the southwest to Illinois and then tow the Kia back, and requires adding a transmission and power steering cooler to it. But that's still a lot of stress on the car and there are no guarantees it can handle it. Alternatively, I can have it shipped for roughly $900 to $1150 (and a flight back after driving the 'trade-in' to them), which I'm trying to avoid as well, but is a possibility.