Vaccum leak on my 2001 Dodge Ram 1500 5.2L

The code PO442 means there is a small leak in the the cars evaporative emmission system. This system contains the fumes that the gasoline gives off instead of letting them into the air and recirculates them back into the intake manifold. The most common cause for this is a loose gas cap. If the cap is not closed tighly then you can cause the system to detect a leak. This will alert the driver with the annoying check engine light coming on. Check the cap and make sure it's tight and then clear the code. If it comes back then do a thorough inspestion of the EVAP system. Make sure to check all hose to and from the fuel tank that go to the manifold and canister.