You would need to borrow or buy a PA Soft 1.4 scanner and check the fault codes. You could have a faulty speed sensor,or mismatched tires,or any number of issues. The best way to diagnose it is with diagnostics. If you or anyone you know does not have the diagnostics,then it sounds like you will have to pay $$$ to get it checked out.
sent from my ATARI sc1224