where did you connect the vacuum source?
the sensor is in the wrong spot,
Connect it to the line going to the bov, if it is already in that spot you need to check the line on the firewall, it is a hard plastic line that connects to a rubber line, i had my line come loose and I had the same problem.
2009 GTR 552AWHP/550TQ
2005 //M 439whp
2009 RR Sport