When I am driving at 75mph or faster, I can look over my hood and see it vibrating up and down from the front near the latch.

When I'm outside of my car I can reach under the hood and lift it 1/5th of an inch. Is there anyway to tighten the hood latch so it doesn't flop around at highway speeds?

 

What year is the car?

 

2000 Civic SI

 

go to link in my signature and find the 96-00 service manual. i assume something is off in your hood latch area or maybe can easily be adjusted as it should not move at any speed.

 

First make sure it latches fully when closed. If you're just on the safety hook it will bounce up and down a lot, and eventually pop open.

I think you'd just loosen the bolts on the receiver (bottom part) of the center latch and move it down, then tighten the bolts. Also check the rubber stops on the sides. They should be adjusted to push the hood up until it is even with the fenders. Ideally when closed the hood should be very slightly sprung with the receiver holding it down in the center and the rubber stops pushing it up at the edges.