Fiat Uno. Engine was reliable enough to shake the rest of the car to bits.
Allegro 1750. Thr HL with the twin-choke choke carb.
Such a dreadful piece of sheet it's amazing it didn't put me off owning a car for life.
Having bought and sold more than 5,000 cars, I find this one quite hard to answer, but I will go with a Renault 30 V6. The Renault 20 was a much nicer and more comfortable vehicle.

) and an Austin Metro which was an electrical problems nightmare, plus the gearbox conked out costing me 500 quid in 1991, which was a fair bit more then than it is now. I think I bought that car on tick for 3 years costing me £1000.