My 05 automatic Corolla engine was always usually pretty quiet but recently it's been a lot louder, not quite like a racecar but something like that. Definitely coming from under the hood too. Last thing I've done to it was spark plugs and brakes but that was weeks/month before it happened. When braking it sounds like a plane engine powering down. I don't think it's the wheel bearings or the alignment. Any ideas?