Yes it's correct.

Yes, if you mean that you wish for something that is impossible. That is, you are wishing that your car would never break down, even if you drive it for 1,000,000,000 miles without fixing it. Even the best car will break down, eventually, so that is impossible.

That is correct, but we would say "I wish my car never broke down" (which sounds like past tense, but is continuous).