Boost Problems

[speedboy109]

I recently looked on nicoclub.com and read up on a boost leak tester. I made one and hooked it up, i used an air compressor at my work and heard a leak coming from somewhere, with hopes of installing a front mount and that might take care of the problem due to less pipeing running around my engine bay. But when i started up my car and started driving i noticed i had boost creap but hella bad, i set my boost guage to 8 psi but can hit like 19 psi at 5000rpm and dont know how i could be doing this. Checked all my lines pipeing etc. everything is hooked up fine. Any suggestions or any advice on how to fix the problem please let me know.