Update:
I took a look under the hood to locate the sound but the sputter was drowned out by the engine noise. It was more apparent underneath the car. So I figured the drive belts and bearings were fine. Heat shields behind the engine were fine too. The sputter was loudest in front of the engine, beneath the drive belt system. And lo and behold there was a heat shield there (exhaust cross over pipe? Catalytic converter? Not sure what the actual part is called) that was just a tiny bit loose. I tightened it up with a hose ring and no noise since.