2006 Mondeo help needed.

[Triple D]

My 2006 Mondeo 1.8 idles at about 1500rpm and randomly revs itself to about 3k revs before dropping back down.

A friend who is usually very good with cars admits even he is stumped. I googled it and found a list as long as my arm of things that "could" be wrong. These range from a buttetfly on the throttle to a pipe in the crank case.

I am not very mechanically minded so thought I would ask you guys before I go throw any money at it. I have asked the same thing I ford section but got no response

Thanks in advance. Cheers