I'm assuming it is a V-6. I don't know of a recall. Most likely intake gasket or PCV hose at the PCV under the intake. If someone washed the engine they got water in the sparkplug tubes and had to remove the intake to get at the back plugs (or they were doing something else for the plugs). Could have knicked or unseated a intake gasket in the process. The short rubber hoses at the top of the intake and below to connect the solid tube for the PVC are famous for drying out, cracking and starting a vacuum leak. The top one is easy and the bottom one requires taking off the intake. So I'd say your going to probably have to pull the intake to see which it is.