Hi y'all, new to the forum and new to vintage Cadillac ownership. Needless to say, the first day has been a ride. I picked up a beautiful 93 deville with 83,000 miles. It ran great on the test drive, and the next day on the ride home after signing the paperwork the car started to act extremely strange. First, when you really gave it some throttle, it would stumble and almost die completely until you let up a bit then it ran smooth. A few more miles down the road, it had the same stumbling and sputtering and dying at part throttle when climbing hills. Finally about 10 miles from home it just shut off on the interstate, which was scary enough. I got it to restart and got it off the road and then let it sit for a bit and limped it the rest of the way home at 5mph, all the faster it would creep in gear, if you gave it gas it would die. I got it home and it was surging like a vacuum leak, I sprayed ether all around the vacuum hoses I could see with the intake off and noted no rpm change, but if I sprayed the area near the distributor it would seem to stumble, but not sure if it was just coincidental because it was having trouble idling. I checked the brake booster by plugging off it's line and no change in the performance of the car, and the fuel pressure regulator didn't have gas in it. All the other lines vacuum lines looked in surprisingly good shape for being 25+ years old. I gave up at this point, no use burning myself trying to work on a hot engine. After the car had cooled, I took it for a ride again and it seemed to run ok. Not great, but didn't stumble and die like it did. The only codes I had were from unhooking the battery and a ISC code which went away after it started idling normal again and not missing. This car is all original it seems, and the only other thing of significance was that the seller filled it up with gas at a small gas station, which I assume he filled it up with 87, but the car was only down a gallon or two when I test drove it so he didn't add that much. To top the night off, the car blew a brake line by the ABS module after the second test beat, so it got towed to my mechanic to look at. I'm just putting out a post to see where we should start to make the car run right. The seller is willing to help me with the repair bill, he offered to take the car back and give me my money back, but this car is clean and finding one in this shape in PA is high near impossible so we decided to see if it can get fixed before it comes to that.