Got a Code P0497 (Low Purge Flow (Code P0497), what should I do first??

What is your question?

I have a 2007 Hyundai Accent 4 cyl 4 door sedan, and got Code P0497, had a previous P0496 and had a purge valve replaced and code went away but now code P0497 came on. Fuel gas cap light is also coming on. What needs to be done to car? Would it be a good idea to have an emission diagnose done first? And would that pinpoint the problem(havin it diagnose at an emission car shop)?