Golf, Black liquid, missing fire, plugs black

[volks1999]

I got few issues with my vw altoghter. New to vw so no idea where to go.

First My car start missing too much. Then i did service, air filter, oil filter, oil and plug changed.

Two days after its starts missing again. Did some test and told that its spark plug3. take out then it looked oily etc. The mechanic told me to change ignition coil pack if not then it could be piston.

So waiting for coil pack to arrive, but today also noticed Black Smoke liquid from exhaust, then checked engine oil which got black color as well. The oil i changed was week ago.

Two times i opened the spark plug and all the time i can see black thing on it. it does not look to me oil(solid black layer) but could be. I changed the plugs yesterday.
Also inside the exhaust its black sticking all around the tailpipe.

So i want to discuss here first as mechanic make a guess and they dont know what is problem. I also dont know good vw mechanic around as never had vw before.

can any profession can tell me what is issue. All all these problems linked with one problem or i have to look at them differently.

thnks for your advice in advance.

the car spec is V W GOLF GTI BLACK METALIC 2LTR year 1999

Also service i did with plugs, oil, filter, air filter are not vw original.

 

[^neo^]

time for a compression test by the sounds of it

 

[volks1999]

hi, thanks for reply.

nothing changed but only what i did is air filter not fixed properly and fixed it. person who did service did not do his job properly and it was bit out from his cover.

then today i went for compression test but guy was busy. so i thought check it first again if its missing.

took to the motorway and drive well about 23 miles with all gears and it seems to me ok so far.

what happened in one day i dont believe and still got doubt it will start missing again.

do u think problem will come again. i am very well montioring now. and will see the progress whole next week.