Engine/Transmission (1998.5 - 2002) Low Boost

[DAvaux]

After having the water/methanol injection for about 9 months, I noticed that my EGT's were getting higher. The air intake is an AFE, so it guessed that the exhaust must be limiting the flow. I just replaced the factory exhaust with a turbo back magnaflow 4". This lowered the EGT's about 100 deg. But I still can't get the turbo boost up much higher than 16 psi. The EGT’s are still higher than what I used to see. And that's even with cranking the TST powermax box up. Any ideas why the turbo is not doing its job? I do not hear any noticeable air leaks, a least from inside the cab. What are the signs of a turbo going bad?