Evening all. I dont know if anyone could give me any advice but i have a 2006 octavia vrs tfsi that has miltek cat back and itg maxogen aswell as shark stage 1 map.today the car when it gets to 4000 rpm feels like it hits a rev limiter and the rev counter goes awol and the car will not go further than 4000 but pulls strongly up to 4000.does anybody have an idea on what it could be?

First thing to do is get a fault code, and take it from there, but sounds like a fueling issue

As above

- 4k not sure but is that where the cam sensor comes into play over the crank? If its on the blink it will retard (may not show up on Vcds though)

Imthinking crank sensor myself, has the cambelt been done?

The cam belt was done October 2010 by skoda and the car despite its mods doesn't get driven hard at all it's just started this today. Is the cam sensor expensive to replace?

could even possibly be the MAF sensor you could try disconnecting the sensor and then see if car does pull past 4k , but do need to check on vcds for codes.