The vacuum lines and elbows are the easiest of all things to be sure of. They're probably the cheapest to replace too. Good luck sussing it out. If your MAP sensor is clear, then hopefully it's only the vacuum lines that need fixing.
Good luck with it, Simon.
And thanks to Sprocket for the explanation about cats. I'm learning heaps on this forum!
Yeah Simon, I think that you should replace all the rubber elbow first(Total of 6 I think)