I had a similar experience recently after changing the oil. It turns out that I spilled some oil and it ran under the engine cover. This allowed the oil to pool in some areas on the top of the engine block. I took a sharp turn the next day and suddenly had smoke pouring out of my hood. I nervously pulled in to a parking lot and tried to figure out what was going on.
Turns out, when I took that turn, some of the pooled oil spilled out of the various crevices it was in and was being burned off as it dripped onto the headers. Pop your engine cover off and see if there's any oil sitting under there.