Rev Shake
 

Took my FR-S on a road trip last weekend. Interstate all the way and got better than 34mpg on the way back. Downside is that I noticed the clicking/shaking sound more than normal. I get this sound at around 2200 rpm and it goes away somewhere north of 2700. It's just a light shake, maybe a resonance, but it's hardly a sound that inspires confidence. Since it's also right where the car cruises at 70-ish, it's more of an issue for that. Anyone know what it is? I can't find anything loose, don't think it's the fuel injectors, and I can't even figure what is shaking.