Plymouth or Chrysler has never had the most reliable cars on the road, but they resonated with consumers nonetheless. The 1967 Plymouth GTX is a notable exception to this because of the unique styling of the car. It was positioned as a luxury car but still managed to have muscle car attributes. The 426 Hemi was an optional engine and although it performed well, its follow-up and reliability were slim.
If you find any of these Plymouths still on the road they are generally reserved for the junkyard. Road salt did not do these bodies justice and rusting was a major problem. If you could beat the rust you would have a decent-looking muscle car, but that isn’t likely.
The Cougar was based on the Mustang, which bode well for the design. But the reliability was a bit different. The Cougar had a lot of shortcomings such as the faulty electrical components in the interior of the car. The carbureted engine had a lot of reliability issues, and this caused a lot of consumers to shift away from the car. You can find these from time to time but they are rare and maintenance is costly.
When you think of the Cougar, you think of the luxury companion to the Ford Mustang. The sad truth is that the Cougar was a let down in a lot of aspects, and the fact that it remains a junkyard find is a testament to that.
The truth is that most AMC models are found in the junkyard. It doesn’t mean that they were explicitly bad cars. But the build quality just wasn’t there at a time when the automotive industry was evolving. The Javelin was known for impressive off-the-line performance and a futuristic design, but when it came to reliability, it just wasn’t there. That’s not to say that the Javelin is a bad car, because it was good in a lot of aspects.
Sadly, if you are going to go for one, you’re probably going to encounter rust. Another thing that happens is that these cars are very hard to come by, and thus parts are hard to come by as well.