weird this post came back when it did, on monday I got into it with an old m3 with an erector set wing, i let him go by but he kept taunting me, passing trucks on the shoulder, doing fly bys. once it was just me and him on the road I caved and ran him, got out front and when it was clear he wasnt catching me i let off, he did a fly by again, let off, and did it AGAIN, so even my wife said lose him so I got back in it and my hood started dancing around 120, looked like the rear was swaying more than anything but I had just checked oil at my last fill up an hour before so i started getting nervous and let out. he passed me again and my hood stopped shaking when i got it back in the doubles. stopped at the next rest stop and hood was close completely and it hasnt done it again since, my splash guard is there but well weathered (stripped 1/4 turns, no threaded bolts, front clip is snapped off) never really thought that could be the problem