Running lean only in boost

[jasonkg]

My car is running lean as soon as I get into positive pressure. It starts sputtering and hesitating and the engine makes a knocking sound. I am able to attain 7 psi.
This started happening directly after I changed out the dump pipe gasket and I got a new intake filter (not the piping). I don't understand how this would give me a problem.

Here is the list of checks I have completed so far:

• Swapped out the mafs twice
• Inspected the intake tube for cracks
• Inspected all couplers for the intercooler
• Inpected fuel pump connector
• Did a FPR test
• Checked timing
• Changed spark plugs
• Inspected fuel lines
• Checked for vacuum leaks
• Swapped out ECU
• Checked turbo for shaft play (none)
• Checked BOV for leaks none (none)

I thought it was a boost leak at first, but it does not appear to be since I checked all parts that would be associated with this problem.

Is there something I missed other than engine internals. It seems like I am having a fuel pressure problem, or a sensor issue. Help please!