Just recently the vents in the car stopped blowing at their full capacity. They blow at about half their usual force even on the highest setting with either hot or cold air. We replaced the in cabin air filter, it was pretty dirty but did not alleviate the problem. The vents will sporadically blow at their full force when the car is not moving, but once we step on the gas they go back down. This led my dad to think that there is a vacuum leak somewhere but this does not happen every time we press on the brake. How would we go about checking for a vacuum leak?


Any advice would be appreciated.