I have a stock 8 Turbo on my car running that has been running 28psi for the past 15K miles. Turbo has 40k miles on it. It currently will peak to only 24psi then fall to about 18psi. Did a boost leak test and found a small leak by the TB but could this be causing the loss of 4psi? Also the turbo spins very free, but if I check for shaft play and try to spin it, the wheel feels like it binds with not much pressure added. What should my next step be?

 

Fix the boost leak, if it doesn't fix it, then see about your turbo.

 

stock turbos wont hold until redline.

perfectly normal

 

The issue is that his peak boost is down 4psi from where it was tuned. There is an issue present..

 

missed those two numbers. replace the seals (or whatever is leaking), they're a common leak-point on most all evos. and yes, any leaks will affect things. the more pressure added the faster the leak will bleed off pressure. 4psi wouldn't be abnormal at all