MKIV GTI engine racing and cutting ou

[sillygilly]

Help, I have an 02 plate GTI that plays up after a long run or if i drive it hard.
It normally starts by over reving and then just cuts out.
My mechanic has thrown the towel in 

[matty james]

   have you had it scanned on vag com ?

[sillygilly]

Nope , what is that ?

[matty james]

has your mechanic looked at the fault codes using vag com .(the onboard diagnostic system)

[sillygilly]

Sorry yes. Sometimes it says its burning rich but thats about it.
Its bizzare , it drives brilliant until I open her up or dribve for a couple of hours. She settles down after a couple of days.

[matty james]

get him to print the fault codes off and then post em up here , that way someone will tell you whats wrong . sounds something simple though 

[Wazzzer]

Top mechanic by the sound of it...

Running rich could be a a number of things, usually the lambda has something to do with it though. If it is you could be well on the way to needing a cat as well