Yes quite a few cars I owned had some weird problems(that is why I got them cheap in the first place!) The one that comes tio my mind, is a Packard caribbean which I bought with a blown transmission , this car had a huge straight 8 cylinder, 359 Cu inch,220HP engine, mated to an Ultramatic auto trans of Packard make, and was the only automatic transmission that I could not fix to my satisfaction,parts for the transmission were difficult to come by, and this was the main root of the problem, I must have stripped and reassembled this trans: at least 6 times. -It would shift into neutral going down a hill, due to loss of hydraulic pressure to the front pump-giving me some heart stopping moments while descending the steep hills of the area I was living in in those days.
It was a lovely car , highly advanced even by today's standards, had an excellent self levelling suspension, air conditioning and power steering that were super, and many other features too numerous to list, I sold it very reluctantly, to a good friend of mine who was desperate to have the car, and who lived in the plains, he had no problems whatsoever with it.