Hi all.

As per the title I'm noticing my van is only making boost intermittently, more often than not it doesn't.

The engine is purring like a kitten otherwise, it doesn't really affect how it drives other than the lack of power, no running rough etc.

I'm a bit lost as to what might be the problem. Pretty sure there isn't a boost leak as I can't hear anything and it does make boost sometimes. I've also replaced all the vacuum piping attached to the turbo and wastegate etc as it was a bit brittle from heat cycling but it has made no difference.

I suspect perhaps the wastegate is somehow stuck open and sometimes for whatever reason it shuts properly hence the intermittent boost. Anyone heard of this problem with these cars, known issue?

As an aside the tube at the base of the airbox that it pulls in air through has a pretty small ID and seems like it would be pretty restrictive, anyone experimented with removing it?

Thanks in advance.