my 97 ford explorerhas 4 monitors that willn't run test?

I have been tring to get the POS inspected ! but the thing has 4 monitors that will not run the test ? I've put over 400 mi on it since it took it in to Midas to get it inspected and it still won't Run Test!! the computor says that it's the Evap,Catalyst ,& 2 Oxygen sensors...