So my sy has been running semi alright the whole time i've had, always having a ticking noise that i swore was an exhaust leak, well after too much mone spent at the local shops I decided to run some compression tests, to find number 6 piston running at about 22 pounds of compression! So as I start to get to the head gasket, I find my 3 pistons on my passenger side are toast! One I can see a ring and the others have wholes in them-what the heck can cause this? The owner before supposedly had the engine rebuilt, perhaps the wrong pistons? Or could it be some chip in there I don't know about that is running the timing totally wrong? Any help would be great