Hi all

I purchased my golf a couple of months ago and had the cambelt & water pump done straight away. It had 112000 on the clock with FSH (nearly all main dealer) and drove very well. On the way to the specialist I use to get the job done I was cruising along the dual carraigeway at 70 thinking how quiet and smooth it was. After it was done I was driving back the other way and couldn't help but notice 2 differences, 1 that it was noticeably more responsive (they said the timing had been about half a tooth out) and 2, it was noticeably louder with a low pitch droning seemingly coming from the engine. I took it back the following day and the technician who did the job got me to take him out for a spin and he said it just sounded like a combustion type noise and was probably the increase in power since the timing was put right. I wasn't convinced though and in the last few weeks it has developed an intermittent flat spot usually when I'm on the dual carraigeway trying to accelerate on a slight incline in 4th or 5th gear. The engine management light doesn't come on and so far it hasn't thrown a fault code. This would usually be attributeable to the turbo wastegate in my experience but I've also noticed a shiney area above the oil filler cap area on the top engine cover. I took the cap off with the engine running and there seemed a fair bit of pressure. The car starts perfectly every time and there is no smoke whatsoever even at higher revs so I doubt it's the rings. Could it be a blocked breather and if so which ones? Would the MAF cause these sort of problems or even the air filter as I did an oil and filter change recently but not the air filter as on inspection it seemed not too bad? I'd also like to ad that my drive is very steep and I usually park nose up as I don't want to kill the DMF constantly reversing up it. Could oil be seeping back into places it shouldn't. I've also noticed the sulphury smell a cat usually gives off a few times in the last week so maybe that could be another consideration. Any suggestions please.