i was going to do a compression test on my car but i was a lil confused. am i supposed to unscrew each spark plug and test them one at a time? , some guy at autozone said i had to remove them all before i plug in the tester and crank my car over. idk bout that
Better to remove all the plugs and then test one cylinder at a time with the throttle wide open. It makes it easier to turn, but WOT makes sure the cylinders fill. If possible to a leakdown test as well, it can be very helpful.