Help with 4.7 jeep valve problem

fishy68, I am 50% with you on that.... I have observed mild suck-up with the paper for misfires but I have also seen it be dramatic for burned exhausts valve or poor exhaust valve seating (worn guides). And it never happens (for me at least) on a smooth idling engine. So it does indicate something it not exhausting evenly; when done right, you look for a very sharp 'smack' of the paper up against the exhaust pipe. .......Maybe I just do it because it is fun....LOL