and the pressure relief valve on top of the IP seems to hold pressure...

A couple other question for you!
As i was taking off the COP i was testing the vacuum diaphragms for the two valves in the intake, both were good but the one in the intake manifold itself took almost 10-15 inHg to open the butterfly! is this normal? what should it take and how much vacuum can the pump generate? Second, what is the best way to clean the intake and COP? seems to be a lot of crud built up in there!!!

thanks