In the pre-purchase inspection on the 65,000 mile CX-5 I just bought, the technician said the PCV valve wasn't working and should be replaced. Since replacing it is a PITA I checked it using the workshop manual process (http://nema.club/2014wsm/workshop manual/n6w01/html/id0116zc800400.html). When I check the end of the ventilation hose, there is suction but it's not very strong - it will hold a small receipt but not a sheet of paper. How strong should the suction be if the PCV valve is working correctly? The only info I can find is not Mazda specific but it all says "strong suction".