Did the transmission downshift before you heard the noise?
No, it happened whenever I'd give it a little more pedal and kick it up to a specific gear (not sure how to discern which gear I was in). It was odd because it only seemed to do it in one middle gear, then when I'd give it even more acceleration into the next highest gear, the noise would stop. No issues with the noise when I got off the highway and was no longer at highway speeds.
TBH, that actually sounds like detonation. Have you ever heard detonation (knock) before? To me, it sounds like a clicking/clinking/rattling sound. Consider trying a tank of premium fuel to see if the sound diminishes.
I've never heard it before, no. I was caught off guard but had been driving for 9 hours by the point I finally hit the NC mountains. I was around the corner from home and didn't notice any acceleration issues, so I just kept going. I'll put premium in it next fill up. Something to get checked out with warranty, or do you think it's fine since it happened under very specific conditions and didn't give me performance issues?
Hard to say without actually hearing it. It may not even be detonation. Most modern engines incorporating computer controls operate under light detonation pretty much any time the driver demands a power increase. IOW, it's pretty much normal operation, but most people don't hear/notice it. Prolonged moderate or greater detonation is cause for concern; it will certainly contribute to increased engine wear, and so should be avoided. Most people would hear/notice moderate detonation.
1. Yeah. I heard a faint weirdness then muted the radio to listen in and try and determine what I was hearing. At first, I thought the "ticking" was something small rattling against the exterior of the car. Then I pinpointed as I drove and knew it was coming from the engine.
Excellent observation! If there is still any of that fuel left in the car you might fill up with premium to bring the average octane for the tank back up to spec.
