If you dont have a gauge check to see if there is excesive air coming from your breather. And check the condition of your oil, if a piston has gone you sould be able to smell the oil it will have a burnt smell. But it would be beter just to get hold of a comp tester. Good luck

if there is spark! and fuel! compression is next..

I couldn't see stem seals causing a big enuff problem to kill a cylinder, (never seen it happen)

i've not had a chance to get a compression test as i dont have gauge myself.
could the oily plug have something to do with compression?

have u done a compression test, if so what readings are u getting

my no.4 cylinder in my a14 isnt firing, i checked the leads and they are working, so figured it must be plugs. replaced all the spark plugs and it's still not firing.
when i removed that plug it was very oily, however i've got no blue smoke or anything on idle or whilst driving.

did some reading and replacing the valve cover gasket + valve stem seals + head gasket seems to be the solution..

am i on the right track? or should there be blue smoke if it's the valve stem seals/ valve cover gasket?

none of the other plugs had oil on them either if it's any help