Hello. So on my father's xjs while tearing into it and replacing some other parts we found 2 spark plugs on the drivers side that are heavily carboned up. He replaced the plugs years ago. All other plugs are clean and look good. This had me thinking valve seals or piston rings? Upon further inspection we found the drivers intake manifold, throttle body, pcv valve covered in oil as well on the inside. Does anyone have some experience with these symptoms? The passenger side intake and throttle body are clean. All 10 other plugs are clean. I don't know to much about these jags and these engine so I'd like some help with this. If it's valve seals or rings I don't think I'm confident enough to tackle those jobs haha thanks everyone in advance.

 

It is worth taking all the PCV stuff off and cleaning it carefully, from the rubber 'bulb' fitting on the front of B bank right through to the intake, including freeing off and cleaning the non return valve in the system (in the pipe going into the back of the airbox) and the wire mesh filter under the rubber bulb.

This might well fix the problem. A bit of oil in the B bank air box from this system is 'normal' but if it gets clogged up, which is does, odd things happen.

Greg

 

I agree with Greg, and along with Greg I have "assumed" you are a LHD car.

This "Drivers side/passengers side" really does depend on where the steering wheel is locataed?????? Please put your location in the HUGE world so us oldies can guess less.

Oil in the "drivers side" air cleaner down here means you got REAL ISSUES, but for LHD cars it is kind of normal, and directly related to lousy servicing pver the years.