More power WITH vacuum leak

[epapp]

Recently my AOS bellows tube had a crack, leading to a P1124 and P1126 whenever I would idle for an extended amount of time. At the same time however, it drove with noticeably more power and a lessened 'flat spot' in the 2000-4500RPM range. Now that I fixed it with a new AOS and bellows tube, it is back (albeit better than before the vacuum leak) to having a slight flat spot in the rpm range. TBH it doesn't drive bad at all, but after having the vacuum leak, I'm curious why there would be more power with the leak...?