Hey Scotty. This might be kind of confusing.... but my 2015 altima 2.5 has been making this weird clatter noise from the engine. Kind of sounds like a tin can rattling but it’s from the engine. You can barely hear it from outside but it echos inside the cabin. Also if I rev the engine, you can hear it as the rpms go up. And it also seems that it was a very lose rpm, comparing to other altimas. It’s got 32000 miles. I got it at 13000 miles. Was a former dealer loaner car. Thanks so much Scotty you’re the only person I can trust.