Originally Posted by
pomtzu
As for the limping - does he ever go outside? Sparky had the same problem a couple of years - first limping and then not (and of course not at the vet), and other issues that would come and go. He was tested for Lyme's and was negative, but it was a false negative, and he actually did have it in spite of being vaccinated against it. A 30 day treatment with antibiotics and he was good as new.
Hoping you can get to the root of that problem, as I know how frustrating it can be.