Legal Question in Credit and Debt Law in Pennsylvania

usually sales tax is collected upon the transfer of the vehicle. if you had a title and tag place process the paperwork perhaps they have a copy of the sales document or perhaps the former owner has the information.

The short answer to your question is yes, you are liable if you never paid it when you should have. If you did pay but it was not turned over that is a different issue and one which you would need the sales documents to resolve

This is strange - a dealer would collect the sales tax and responsible for remitting it. Did you buy the vehicle from a car dealer? If this was a sale from a private party, does the DMV collect that when you re-title the car in your name? Or does the state rely on you to report it and you did not do it?

Answers to these questions will dictate what you do. If the sales tax was collected from the dealer and he did not turn it over, there would proof that you paid and maybe the revenue department will go after the dealer. If this was a private seller and you did not pay the sales tax you may have to pay. However, without seeing the tax notice here its difficult to know what is going on.