Just a process of elimination to find the cause. It should not be billowing smoke... duh.
1. pull your oil dipstick and look closely at the oil. Was it overfilled? Oil overfill will kill your new AOS quick. It should be clean and golden in color. If it looks like a milkshake you have a coolant/oil intermix problem. Open the coolant reservoir when cool and check same. If both look clean you can now celebrate with a beer.
2. make sure your intake, throttle body and cats are clean of excess oil. (they can load up pretty fast with a bad AOS and it takes a while to burn it all off.
3. Monitor your oil and coolant levels to see if either are dropping. They should be very stable for 4000 miles or more.
4. If you have not yet found a problem you can pull and inspect the spark plugs or have a leakdown test performed to see if one or more cylinders has failed.
Plenty of things to check. Let us know what you find.