Nothing beats the process of smoke testing the vacuum issues. The hose run every where and I can understand the easy target the gas cap. The cost of equipment to run the test vs paying a shop is for you to decide. I am assuming all valves are working right and there is a vacuum leak

Salim

 

The quick things to check are the gas cap and the hose connected to the airbox. After that there's no quick solution. This thread and other like it give you test procedures for the canister itself and the hoses and VSV's. There is a sticker under the hood with a vacuum lines and switches diagram. A vacuum tester to test hoses and VSV's isn't expensive .