my fiat punto is only firing on 3 cylinders

[benrobs]

i have recently perchased a punto 1.2 16valve sporting it is sreg and has only done 70 thousand miles i paid �250 for it it has 16" wheels and is in mint condition inside and out but there is oil getting into one of the cylinders preventing the spark plug firing when i take the ht lead out it is soaked in oil and so is the plug top i bought the car in this condition thinking i could make money on it do you think it is an expnsive job and would it be worth getting it done

[NORMANTHEDOG]

dosent the fact that you only paid �250 for it tell you somethink

[steve2010]

maybe the rocker cover gasket has failed and is leakin into the cylinder, try that, good luck

[Toureman]

Ignore Steve's guess, the rocker cover gasket has nothing to do with letting oil into the cylinders.

Probably broken piston rings or scored cylinder or valve seals gone.

[Toureman]

I forgot to say could be cylinder head gasket broken between cylinder and oil way.

[NORMANTHEDOG]

toureman,steve could have a point,if the rocker cover is leaking,the oil could be going in to that plugs well and causing a problem. read the question,oil on plug top and lead.so steve could be right mate

[keeeno]

hi, check to see if the plug is firing first. remove the offending cylinder ht lead and plug. reconnect the HT lead to the plug and rest it on the rockerbox cover to earth it. fire up the engine and see if the plug is sparking-DONT TOUCH IT WHILE THE ENGINE IS RUNNING! If it sparks you know its either cos of the oil or its because of petrol. check the injectors by swapping them over and see if this helps.
the oil shouldnt get into the plug lead top - its almost air tight (or should be), so should have no affect on the conduction of the plug electrically.
To be honest its likely that if the car's been ragged in its life (being a sporting!) you'll have scored bores and oil is seeping up from under the cylinders. Mind, the head gasket life is supposed to be 60k miles so you might be overdue a change. At worst, you might have a cracked cylinder head leaking lots of oil into the cylinder.
Steve's idea will cost you about �6 to replace the rockerbox seal...hope any of this helps!

[benrobs]

thanks for all your answers it turns out that the rocker box cover is leaking onto the top of the plug its missfiring because two injectors need replacing ive had it put on a diagnostic machine the car had the head gasket replaced 7 months ago and its never been ragged its only had one former owner and he is a freind of mine so it looks like the car was worth it after all