MP8 low boost

[GoldDog44]

I have 2 2014 CHUs with MP8s. Both deleted. Right after the EGR delete both lost boost pressure and they are short on power. There is what seems to be an exhaust leak whistle on both and the turbos are sluggish. Can’t get more that 31 psi. There is no black soot trail that would point out the exhaust leak. Does anyone know if there is a way to back pressurize the exhaust through the turbo to find any leaks? Has it been done before? I changed both exhaust manifolds to remedy the issue and still no dice. I’m thinking it’s the EGR blocker plate but like I said there is no sign of soot anywhere.