Lack of boost

[Paul257]

Hi asking for a friend

Cheers in advance

HELP!! before I kill this van.. .

Mk7 2.2 euro5 transit.

Turbo went. Changed turbo, ran fine for a couple of days, now boosting and pulling fine till 2500-3000 revs, then goes into under boost.

I'm thinking map sensor full of crap after turbo failing.....