My boost pressure keeps getting lower and lower as the engine warms. Also every time I drive the car the peak pressure is a little lower than last time. For example, I made about a 20 mile round trip down the interstate and back. Starting out my boost pressure was about 20 psi on the way back I could only hit 12 psi. I let the car cool for 30 minutes and was able to hit 17 psi. That was October third. On October 10th I took a very short cruise of maybe 5 miles and hit boost three times. First hit about 15 psi, then 12, then could only get 8 psi. This was with no hoses connected to the wastegate. Ther car had been working great until recently running 25 psi. I had the turbo rebuilt in 2011 with maybe 5000 miles put on it since. It's a garrett TC4305 58mm with .82 tubine housing, 3" exhaust dumping about 24" from the turbo. So what I've done so far to diagnose the problem...First I removed the wastegate. It's a turbonetics evolution wastegate. I disassemble it thinking the spring may have been broken. Nope it's fine. I applied regulated air pressure to the bottom port and it cracks open at 15 psi. I also fabricated a tool to see how much back pressure it takes to open the gate. It leaks with only 1psi applied. So I disassebled the gate again and lapped the valve to ensure a good seal and retested. Still leaks with 1psi applied. This does not seem normal to me but I don't see and physical problems with the wastegate as everything appears ok. I also used a smoke machine to check for leaks in the intake, piping, and intercooler and found nothing. Anyone have any input or things I need to check? I will attach my datalogs. Thanks