wont show fuel pressure on obd mate as its just a mechanical pump. it mite give a squirt but it mite not b enough pressure on demand. if the cars running lean the ecu will try to do what it can to richen it up. id def change the fuel filter mate (they easy to fit and cheap). you have to do a fuel pressure test on the rail mate, after that mileage the pump mite b tired out not being able to give the pressure when needed. would cause a lean misfire and b ok at light load