For the longest time I had a squeak that only happened on bumpy roads and it was driving me nuts. I thought it may have been coming from behind the dash somewhere but it wasn't. One day when getting out of the Jeep my now wife slammed her door a little bit harder than usual and I heard the squeak. So I told her to do that again and she softly closed the door thinking I was mad (I'm usually kinda anal about slamming my doors). So I had her shut it hard again and I heard it coming from the front of the Jeep. About two more slams and I found it. It was the hood catch! A little bit of grease where it rubs and no more squeak. I recently cleaned the engine compartment and it's come back but I was reminded of it today when I was disabling my daytime running lights.
