SAME PROBLEM! I noticed it was reving a little too high for being in park off a cold start. It was doing it by itself, up to around 1.5-2 rpms. It might be the code being throw for the air injection pump. Code is: p0410. It caused my engine light to come on. So I ordered one hoping it will help. But this random reving stopped after 10 sec and this is the first time I've seen this happen.