So I have been struggling to find out why I am not boosting as much. I do have an aftermarket turbo is 64/74/14 industrial injection turbo. I am running hot rod vp 6x18 injectors. Stage three cam headstuds. Ported polished heads. I usually push about 50psi but all of sudden just can't get passed 30... Only code was p0217 which is low performance due to over heating so I went and change thermostat and coolant sensor and I do run cooler now and in hooked battery's to reset code. And it still won't boost... I did notice the turbo is starting to leak oil between exhaust and intake side. Which is a sign. And I also blowing black smoke like I usually am it's more grey. Idk is a bad turbo? Or something else I don't have shaft play. The turbo was rebuilt in 2012 as its stamped on it. Could there be anything else?

 

Turbo is not building PSI or you are loosing it out a boost leak, more likely.

 

What happened to mine was the inner fender slit the boot at the lower drivers connection. It was small but I could hear it and my truck lagged a bit. Look there...

 

I have seen the lower boots get rubbed on the inner metal fender well and make a rip many times on either side on the truck.
That is a good place to start chasing boost leaks on a 2nd gen, good point SIXSLUG.

 

It is pretty sharp where the fender seam joins, I rolled mine under and outward after I found the cut in the boot.