As you can see from my threads this octavia has been a pain in the arse to fault find, but i am pleased to say my boost issues are resolved. I replaced the diverter, replaced all intercooler / turbo o-rings for green seals, replaced plugs, replaced coil packs for red units, replaced maf, replaced pcv and gasket, hpfp and lifter replaced. Car now pulls well all the way through the rev range, BUT now the revs are slow to drop, sometimes even sit at 2k before slowly returning to 800, only non gen part is the pcv ! Could this be the issue or clutch switch ? Octavia mk2 vrs 2.0 tfsi

Breather pipe leaks? It could be related to the PCV replacement.  The plastic 2 pin connection of one of the connections is a weak spot and can break.  Is it an unbranded pattern part?  Other than that, vacuum leak or throttle body.

Pcv is aftermarket, all other parts genuine

IMO you need to get it plugged into VCDS and get a scan done and I would also get rid of the cone filter and go back to std airbox.

 

Struggle for access to vcds hence replacing every part known to man 😂, as a rule i dont like cone filters but this came already fitted. Would love to get rid of it. Is it a common thing for cones to mess these up ? Apart from heatsoak