Looking for some advice, for a few months now my car (Skods Fabia 1.4 TDI) has been losing power but it's only an intermittent problem. 

The symptoms that I noticed when I loose power:

No power for overtaking

Slow acceleration up to 70 mph

This only happens when i'm on the motorway but I do alot of motorway driving. Doesn't matter if i have only covered over 5 miles or 30 miles it losing power and it's intermttent which is annoying! 

Diagnosed car with a PO234 fault.... Anyone have an idea of what could be the fault?

From Ross-Tech's Wiki:

http://wiki.ross-tech.com/wiki/index.php/16618/P0234/000564

Thank you!

Thinking where to start.... Firstly need to check it's nothing to do with the hoses before i change any sensors!