hi .iveco isn't my thing ,afraid i'm daf lol... but if you have no boost then it does sound like a turbo issue ,but as you suggest clean the vgt ...just make sure the air filter is servicable ,the amount of probs ive dealt with and it's a duff airfilter ....remember in trucks of old a duff air filter would give you black smoke ,but nowdays electronics take care and prevent it ..make sure all intercooler hoses and clamps are ok ...pressurise the intercooer to make sure it isn't leaking
norb
May 2011