Boost is flying up to 0.5 (bar) and dropping straight back to .25 which would point to a boost leak but every thing is tight and ive checked every thing for a leaks again and again. it has held boost fine before. Is there a way that i can test it to find a leak?

 

check to see if the fire ring in the wastegate is sealing correctly

 

How do i do that? i have an internal wastegate if it makes any difference.

 

anyone?