Low compression... Rebuild or New Motor?

[Tacomarunner]

Recently the 'ol dog was running rough, took her to FORD.
Results: #8 cylinder missing on low compression. Ran codes, has code for #8 contribution. Did an injector electrical test and passed. Did a relative compression test and found #8 cylinder low on compresssion. Did a blow by test and it had 16" of vacuum on the blow by the max is 8" of vaccuum.

Now my question is: Is this mostly likely rings? Oil is also cominig out the exhaust, pretty sure its because of the blow by. Could it be from bad valves? Any help is appreciated. Any info needed?

Thanks, Russell

[fordmasterdieseltech]

Valves, rings, piston or cylinder issue. could be any of them. best bet is to tear down and inspect, once you find the cause, then you can make a educated decision on what to do.