how much does it normally cost to run a diagnostics test on a 2005 ford exhibition

You can go to AutoZone or any parts dealer who will allow you to plug an OBD2 into your cars diagnostic socket for free. If you ask someone they may even do it for you and tell you what they found .... Problems will appear on the screen if you have any

If you are behind on service work, and can get that updated, you may find part of your concern at least. The codes mentioned by tom can help you give the parts an inspection. The Ford garage has the best techs for a no nonsense fix and complete diagnosis of codes and runability concerns. Any properly equipped shop is going to charge for the first hour as a beginning. Pick what you want to pay based on the labor rate charged in your area, they are not all the same. You can also google the codes and get more info based on your vehicle info. Emission recalls and TSB's can be found at your dealer service department. They also have the right updated parts for the system, best and first.