The experience of yours and the Audi reminds me of the first station wagon we had. We had just sold our house in Nampa and I was working on TVs. We bought a Chevy in Portland at Honest John's and it seemed like a good car, the only wear was the driver's seat.
We had used it about a week and had a flat tire. We took the tire in to have it fixed and the tire man said the tire had been re-grooved through three belts, so we checked the others and found the same thing. new set of tires. Felt so good we decided to go to Nampa for the weekend.
Needed a tune up first, so we took it in and they worked on it and said it still had a little miss but OK. in La Grande it developed a severe knock so we went to a mechanic and he said it was quitting and couldn't work on it. Just go on and drive a little slower. He said we had a valve that was sticking. the next day in Nampa we took it to the Chevy garage and they thought the same thing. We needed a valve job. When they broke it down they discovered a broken valve an a chipped piston. we drove back to Kalama and we still had a little miss.
A few days later I was driving home from Longview and heard a clunk and the motor died. It was after dark so with flashlight in hand I checked the motor for what I thought would be a broken fan belt. The fan belt was OK but as I ran the light back over the motor I could see two pistons looking like they were ashamed to be seem all undressed like that. I walked down to the Kalama River Trailer Park and had a heck of a time convincing Billy what had happened. He couldn't believe a Chevy would do that. he finally called Harry Becker and he came out and pulled me home. That was on Tuesday and on Thursday we had a complete motor put in and Friday we drove it down to Woodland and traded for a Ford. a really trouble free car. A lot of TV earning down the drain.
Now the rest of the story. About six months later we were at the dealership where we traded in the Chevy and the manager came over and asked what was wrong with that station wagon. I had showed him the papers on the new motor when we traded. He said they sold the Chevy and had to replace valves and pistons twice and the car didn't sit straight and they even bent the frame and couldn't fix it. They ended up taking the Chevy back and took it took it to a junkyard and disposed of it.