[Steve T]

It's not needed with newer cars. The computer will actually set lots of faults if it is wearing out. You can have your dealer run a test and give you the actual reading and the specified reading just so you have an idea. If one cylinder is muchlower or higher than the other, I would suspect a problem. A much higher reading indicates oil rings have failed. A much lower reading indicates a valve leaking, EXTREME scoring, or bore wear.

What would be considered a "newer car"?

 

[ndrewoods]

Cars that use "power" auto parts like power steering, power window, power door locks and etc. Newer cars have computers built within it to diagnose it for you like for example if it shows that a good portion of the roughness/loudness is from the rear engine mounts and the transmission mount. Hope it helps.