This is a question of causation. Like people, sick cars can deteriorate quickly, and it is not clear that the mechanic exacerbated the problem. Based on your own description, it seems that the mechanic didn't cause a new problem - he just didn't fix the one you had. The symptoms are practically identical.
It is clear that you don't trust this mechanic, and it seems they don't have the skills to fix the car at this point. Therefore, trying to get them to do something for free or a discount seems to be off the table.
You can consult an attorney about a suit, and I suspect you can find one to represent you, but you'll likely have to pay them. I doubt that's worth it. If you can find one to do it on a contingency basis, you will still pay in the end if you win, but you won't have to come out of pocket. I doubt you will get a lawyer to take this on contingency as there's not a big pay out. Plus, you will likely need to get the car fixed in order to determine the cost to do so and establish your damages.
If it were me, I'd ask the first mechanic for a refund (you can tell them they're lucky you're not suing them). Then I'd go get it fixed to at least have wheels to visit attorneys:)
Answered on Mar 12th, 2012 at 7:37 PM