I spent a good hour or two this morning sucking on different vacuum tubes. They all seem to be okay except for two that exit the engine right below the air mass meter. One exits there and heads toward the valve cover and the other goes to a relay and on into the driver side front panel. I took off both hoses and there were no leaks, but when I pull out the distal end (leaving them attached under the AMM) then there is an air leak. Is this normal? Is there a direct connection between the AMM and these hoses, and if so how is a vacuum ever created.