I have a 2008 3.7l that apparently has a cylinder 4 misfire. I changed spark plugs to ngk ones no success. I cleared the code and tried swapping coil packs with cylinder 2 to see if the problem would follow and it still made same noise but I couldn’t get a code out of it. It makes a loud tick/tap noise about every 3 seconds or faster if you rev it. Kind of sounds like you’re tapping aluminum Any ideas?