pressure test line comming from fuel tank,one of two ways,1.disconect line from fuel filter on side where fuel line connects from fuel tank,if pressure 26psi to 35psi reconnect line to filter and check your line on other side of filter if pressure holds your fuel pump and fuel filter are ok,the other way is to disconnect inlet line from tank to fuel regulator and check your fuel pressure,the only thing with this method is if your fuel filter is clogging or clogged you will not get an accurate fuel psi.you can also check your fuel regulator,you fuses,or your relays to anything that has to do with your,depending on what type of car you have