2014Lowrado

I have a 2014 Silverado with a 4.3 V6. About a month after I got it, I've had it for over a year now, it started having a knocking noise. Did the obvious and changed the oil. Still there. Threw some Lucas in it. Still no difference. I ran Seafoam through both the oiling system and the fuel system. Knock Knock. Pulled the intake and valve covers, checked the valves(nothing wrong other than being dirty). All the rockers were tight. Now yes, my first assumption was rod bearing. I just wanted the check all the easy stuff first. Also, I fail to believe it's a rod knock because I beat on the truck a good bit. It hasn't got any louder. I'll add that it sometimes does it at idle, will only come in while driving when I hit 2000rpms, and goes away when it hits 3500rpm. Someone please help. It's obviously not affecting the performance or getting any worse. I just hate hearing the sound. Any help or suggestions is greatly appreciated.