I put about 60 miles on the car today, mostly highway driving in the rain. When I got home I got out of the car to investigate my windshield wiper squeak and noticed that the engine was knocking pretty loudly. It increased in tempo with the RPMs. I popped the hood and couldn't hear it much from above. The sound was definitely coming from the underside of the engine.

I came inside and spent about 20 minutes searching the forums and after reading this thread I went back out to see if it disappeared at higher RPMs. The knock was gone, so I drove around town for a while, including some highway, and the knock didn't come back.

I'm having the car looked at Monday for a handful of other issues. Is this worth mentioning? I work with computers for a living, so I understand if the problem isn't reproducible it can be very difficult to troubleshoot. Also, I'm only 1.5k into this oil change, and the dealer changed the oil before I bought the car, so I don't know what they used. Seeing as oil changes are expensive for this guy I'd rather not preemptively change it. Also, I'm half a tank into 93 octane (it's all I use).

Thanks,
Spencer