mk4 vw golf, engine revs by itself + runs rough + starting probs?

Please help,I have a mk 4 vw golf,1.4 petrol,60'000 miles.the engine used to cut out alot and it was traced to a build up of oil around the butterfly valve beneath the airbox,I was told it was a common fault and was fixed easily.But now after a few months of running fine its began to have trouble starting,sometimes floods with fuel but doesnt start,sometimes starts fine,It also runs rough missfireing and sometimes the revs increase to 3000rpm by itself,I tryed cleaning up this butterfly valve again + tryed putting it on a diagnostic machine but as its intermittant its hard to trace.Please could anyone help us out?