Very odd. I tighten my chrome grill some plus put some bumpers behind the hood so it would not vibrate when driving.
I never had any noise like your experiencing. But our hood and grills are a little different.
So at lower speeds you dont have this problem? Only interstate speeds?
2017 Axis / 25.4: Big Foot Levelers, Aims 1200 Watt inverter, Ceramic Window Tint, Full River AGM 6V batteries, Front Hellwig Sway bar / Rear Track Arm, Safe T Plus Steering Stabilizer, PD 4655 converter, Hard Wired Surge Guard, WEboost + WiFi Ranger, LED Headlights/Driving lights, Fresh water surge tank, Black Tank Tornado flush, 4999 zip ties.