So this reply is a little late, but I had this problem for a long time and just dealt with it. Then I had someone tell me to replace the check valve. Its inline on a vac hose in the engine bay. It was a $9 part at a dealer and took all of 3 minutes to replace. It still does it once in a while, but honestly, I don't really even notice it that often. And when it does do it, I just turn down how hard its blowing and it comes right back in line. Seems like its a vac issue on most. I even bought a new vac canister, but never installed it since its been working 95% of the time.