I am new to the thread read it all the time has saved a car or 2 my problem is I have a 2006 expedition 5.4 3 valve 160xxx miles and I just put a lot of work in it my wife bought it about a month ago from a guy who said he had a "shop" do all the timing stuff cam phasers timing chain and guides but it still ran like hell so me and my father after looking at it and tearing into it decided the timing was out and it was way out the new cam phaser on the passenger side was junk so to make a long story short about 2 grand and a lot of new parts later we got it timed right New cam phaser s oil pump 3 of the rollers had play so we changed them New valve cover gaskets New timing cover and gasket New intake plugs coils I'm sure I'm forgetting some other stuff got it together and we r losing oil not leaking oil it's just disappearing well hooked the computer up and it says cylinder 5 is 33 percent on the negative side but what doesn't make since to me is if that cylinder is dead why does it still run decent u can only tell if u give it gas and there is blow by air coming out of the oil cap any suggestion

 

When you say "cylinder 5 is 33 percent on negative side", is this a relative compression test or a power balance test? Both can be done through a computer. If you havent run a relative compression test, do it. If you have indications of weak compression on cylinder 5 in this test, with the air coming from the oil cap, chances are you have worn piston rings.

 

I agree with Skauber that you need to clarify what you mean by this.