I can't imagine what the target buyer was for this car in 1978 - much less now. 1978 Peugeot 504 Turbo Diesel - cars & trucks - by dealer - vehicle... (craigslist.org)
A high school buddy of my older brother had one of these, but I can't remember the model year. Anyway, it was no real powerhouse, but it was comfortable, and fairly roomy.
I had a former coworker that swore by the wagon version of these, he put over 500,000 miles on one in the 80-90's. Only really had suspension issues but I think that was mostly due to the "Great" Michigan roads. It got over 45 MPG and he loved it. It was way to slow for me the couple of times I rode in it. But it was a good riding car. He loved it. His was and early 80's version, and a manual trans car.
My brother's friend's car had the auto trans, and it was factory set up so that it would not upshift past Second till the engine reached, I think, 140 Deg. F.