So I've had my X for about 3 weeks now. About a week into having it(of course), it popped a CEL so I had my friend plug in and read the code but it only popped up with a knock sensor. Car was riding fine so he told me not to worry about it too much. That it it starts giving you an issues, we'll spend the day tearing it up and replacing/relocating it. So fast forward a week later the CEL pops again but I start noticing this odd vibration when I'm cruising and I'm hitting around 2k RPMS. It only lasts lik half a second. Feels like I ran over a bunch of cat eyes with my rear tires. I also read here that Knock Sensor wouldn't trip a CEL on its own. So why isn't anything else coming on through codes? Also notice some rough idle so I've ran two tanks of highest grade gas and I've noticed a slight change but it's still noticeable. Any idea if these things are related? Any idea what's going on? I'm heading to autozone today to get this read and see if they can pull a different code. Thanks to everyone in advance!