Ok so I will admit when I'm wrong and say that ImStricken was right, it is coming from my windshield... And I want to say that ever since the day that I made this thread (hearing it for the first time), I hear it more and more. More and more to the point of hearing noises while just hitting slight bumps, etc.
So I was going to come on here and complain about that, however, something struck me tonight and a little light bulb turned on in my head (ImStricken you may appreciate this)...
So I am into retrofitting headlights with HID projectors. I did that with my Accord, etc. In order to do a retrofit, you have to bake open your headlights, install the projectors into the reflectors, and scrape off the old headlight sealant and replace with butyl (ironically what they mount windshields with), clamp your headlight lenses back together, and bake them again.
WELLL, when I suction mounted my green and white POV lights to my front windshield, I used thin lines of butyl to kind of "secure" the shrouds of the lights to the windshield so they wouldn't be shaking and bouncing... Pics of the butyl:
For those who don't know, butyl is semi-hard and very tacky when cold, and when baked it becomes soft and spongy... Obviously I stuck the butyl on there when cold... My theory is that when I initially came out of the driveway of that gas station I made this thread about, when the windshield was trying to flex, the lights may have been "fighting" it since the butyl kind of "stuck" them to the windshield, and the popping sounds I heard was the butyl losing its adhesion to the windshield. I noticed on my drive home that day that both lights were no longer stuck to the windshield and I had to press them back on (They had never lost their adhesion before that day, and as I said, the butyl is very tacky and sticky). Ever since that day though, they have not stuck to the windshield as well, and I had to reapply the butyl to cover more surface area to stick better.
Is it possible that the sounds I'm hearing are just the butyl "fighting" to adhere to the windshield ever since that day?
I know my best bet is to un-stick the lights from the windshield and drive around to see, but I just thought I'd run it by you guys and see what you thought! Deep down part of me thinks that the original popping noises I heard may have been a little too loud and too long in duration to be the thin strips of butyl, but I guess I honestly don't want to find out that it is something out of my control (bad windshield installation) that I'd need someone else to fix

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Also, ImStricken, what would you recommend using in place of the butyl if it is in fact the problem?
Thanks guys!