Sounds like a bad deal on, your part anyway, but having sold a couple of used cars, one of them just recently, I have to say it's pretty much buyer beware. I sold one car that was my daily driver for 5 years and never had a problem. The guy drove it,liked it, bought it. Calls me 2 weeks later and says it blew up the first day he drove it to work and wants his money back. Says he was sick the whole time and the car was just sitting and just used it for the first time. I asked if he checked the water in the rad and oil. He says no. I asked if it overheated. He says he has no idea but I must've known there was something wrong with it when I sold it to him. I told him if he didn't know anything about cars he should just buy a new one that comes with a warranty. Recently I sold a 95 Dodge 15 pass commuter van w/90K orig miles. The trans had gone out and I let the registration laps and the ins. The engine(360FI Magnum) ran ran perfect, interior was near perfect. I sold it for $800 because it had been taking up my driveway for 3years and I wanted it gone. So the guy buys it then a week later calls me and says DMV wanted too much for reg and he wanted to bring it back. WTF???? I say no and he says he'll have to sue me. WTF???
The way I see it if there wasn't any issues with a used car the person wouldn't be selling it. It's up to the buyer to find out why and if it's still worth it to him. I feel for you buddy but do your own homework and don't rely on others to do it for you.