I know i have a vacuum leak my vents go to defrost when i accel and im getting like 15 mpg gas mileage. My problem is i dont know where to start to find the leak and fix it. Not an expert on vacuum lines what they look like or where i should look. since the vents only default to defrost when rpms are up im thinking a crack or a hose is slideing off when pressure builds which would be harder to find. Im makeing a 2200 mile trip in 3 weeks and 2 of those weeks ill be out at sea i need to get this fixed fast.