I was just wondering if anybody had any ideas as to the huming noise i'm hearing inside the ty. I only hear it when its going into boost, not even at WOT, it seems like there is a vacume leak under the pas. side dash.
There should be a check valve that isolates your heating and a/c vacuum from engine vacuum/boost. Perhaps it is missing or defective. Refer to the vacuum diagram under the hood for location.
