engine keen cutting off

Hi
I have got a 2004 polo FSI when i start the car it cut out. I change the oil , oil filter air filter plugs but the problem is still there. mysteriously some time do not cut out 1 or 2 weeks and then start cutting out again. The only thing to prevent this to take the engine oil cap off to let some air in for a 5 to 10 minute then it run again for days. And some time it keep cutting off. The mechanic say this could be a camshaft sensor or may be something else. There is no warning light to say there a problem. So I don’t want to spend on so many different thing and it end up it some thing else. Could you please let me know if this kind of problem been cause by the camshaft sensor.
I mean when the engine oil cap is off the engine is run fine no cutting at all
Thank you for you help

Oil breather pipes are blocked by the sounds of it

thank you for your reply
could you let me know is this a big job to do it. and what sort of cost would i expact for it. or if there is some thing i can do to repair it. i been serviceing the car my self must of the time.
thank you

find the pipe going from the top engine cover to the inlet manifold or air filter box, pull it off, give it a clean out or just replace it, make sure the port on the engine and inle are also clear.

ps, dont start it up without the pipe there, you will spash oil everywere

Hi
Thank you for your help and support.
Any way i kind of give up on the car i thought let me to take it to a locale garage. Before that i thought let me clean the throttle body to see if dirty. Any way i open the throttle it was very dirty and it was full of black sut. I gave a good clean to the throttle body. And as i cleaning the in side where the throttle body is set on. I saw there was a metal breather pipe was run from there to the manifold with the hexagon head like a fan shape . as i was cleaning the inside that pipe was completely block i thought this is some kind of sensor i thought i don’t want to damage any thing here as i don’t have the manual for this car to direct me to what is this pipe for. Any way as i was cleaning it with a little screw driver then suddenly the screw driver went in to the dirt and make a hole. And then the shape of the pipe is emerge and become clear what is it and i give a good clean with the carburettor cleaner. Clear all the dirt out of that venture. And install the clean throttle body.
Start the car and boom. The car is run like a brand new engine. I believe the throttle should be clean every 20000 to 30000 miles. Because my car done 34000 mile and the throttle clogged off.
Any way i hope this information help somebody if they got the same problem.
Thank you

Well done neo and timtheenchanter. Nice to read about a complete cure and a happy forum member.

Glad you got it sorted.
I notice you say you're servicing it yourself........... are you using genuine VW filters or something off the shelf from Halfrauds?
Same goes for the oil?

Hi
thank you for watching me neo. I got the oil and air filters from Euro part

You'll be surprised how resonable the parts are from VW, and the oil filter unlike many of the aftermarket ones has a pressure relief valve in it. For the sake of 50p or so extra it's worth it!

Hi
Thank you for your advice. But let me tall the story about cat for this car. Year and half a go the second cat is gone all the locale mechanic was surprise to see this such a young car the cat are gone. Any way i took it to so many mechanic they order the cat they told me it cost me £275.00 labour and part. I say that fine. Even it not genuine VW part. When the cat come. the mechanic say this is too mechanical to fit. He say it cost you £600 to fit this cat. They told me you can find the cat for all other cars. but this the cat is too mechanical to fit. i say if i replace the second cat and what about if the first cat is gone after while. i thought let me replace it with original both of them. The VW part department told me only to buy the complete cat because they are 2 cat together it cost you £1300 less £ 250 when you bring the old one back. And plus £300 cost of the labour if i want fix it by the VW. Which is the total of £1600 for just a cat i can’t believe how they can charge massive amount of money for 1 cat. Any way then find the second cat one line from another company. I told them is this is the correct cat for this car, he told me yes this is the correct cat for it. but you have to cut the other cat to suite this cat. It cost me £110 for the cat including delivery. And it take me 2 hours to do all the job. It still going pass 2 MOT no problem