2002 Octavia VRS Error code

Hello everyone!

My 2002 Octavia VRS (petrol) has recently started to loose boost pressure and the acceleration is 'lumpy' (although on full throttle appears fine), idle is fine and other than the 'lumpiness' the car drives OK.

It has had a remap recently and I have also replaced the following parts;

• Fuel filter
  
• Oil Filter
  
• Air filter element
  
• Spark Plugs
  
• Cell Packs
  
• Air Mass sensor
  
• Various pipework
  

After taking it to a garage the error code read as P1296 and I have read a couple of forums that suggest it could be the N75 valve. Before I go and purchase one I was hoping someone may know if this is the most likely cause?

Cheers for any help or guidance!

Barry