when I run.. I boost all 18psi even in first gear. I had a custom 3" downpipe fabricated and a 3" cat mated to a custom mandrel bent 3" exhaust system. I get no boost creep. If you're not boostin above 1psi with a greddy evo exhaust..you're more than likely leaking boost. Yea..it would be a good idea to check all hose clamps and vacuum lines. when I forgot to connect my vacuum line to my bov I also was able to hit 1psi but no more than that due to the leak.