Don't ignore the elephant in the room- - - - -worn out piston rings. Do a cylinder leakdown test to see how much compression loss you're getting. A "compression test" is sort of a "wild-donkey guess"- - - -putting air pressure in the cylinders is a much better diagnostic procedure.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!