I have a whistling noise coming from under the hood. It only happens when my foot is on the gas pedal. Any idea what this could be? 2005 Honda civic.
Could be a loose belt or one of the idler pulleys going bad. Does it sound like it is around the belts? If so inspect belts. If tensioner and all appear to be as they should but noise continues get a piece of PVC pipe or hard vacuum cleaner hose and carefully position it in and around the pulleys while holding the other end to your ear. The noise will get much louder when you get close to the item that is making it. When problem is located repair as needed.
I took the belts off and checked the idler pullys for play,looseness, and to make sure they rolled fine. They did. I don't think the noise is coming from the belts, someone from work suggested it could be a vaccum leak. Do you think this could be the problem?
It is possible but if it bad enough for you to hear it whistling I would think that you would have drivability issues too.