Strange spark plug fail M128

[Micker747]

I'm experiencing a strange spark plug failure on cylinder 3, plugs, cables, coil etc are all new oem.
The engine starts on 5 cylinders and number 3 does not ignite. If I then clean the spark plug with brake cleaner, it will run on all 6!
As soon as the engine cools down again, it will run on 5 cylinders. I can keep repeating this, but I'd rather fix the problem..

The engine runs normal and does not smoke or use much oil. Could it be oil seeping thru a valve stem seal or a loose valve guide, soaking the plug?

Regards

Michael

[ja17]

If so, it will be the intake guide which is the problem.  Start off checking the compression on all six. Since it could be an injector, move it to a different cylinder and see if the problem moves.

[Micker747]

Thank you,

Is it possible to change the valve guide seals without  removing the cylinder head?

Regards

[ja17]

Yes but if the guides are worn, the new seals will jump off or will not last.