[Abutterfly]

Hi everyone. Could I get some feedback on this little annoying thing.....I am driving a 2000 Sahara 5 speed. I have had this happen a few times since I got this thing maybe 10 months ago. I have had it happen maybe 5 times in the last 4 days or so.
I am driving along.... when the light turns yellow or I am coming to a stop... I put the clutch in.. and then I put the shift in N... and I am braking in total neutral and I get this vibration under my brake foot. I am thinking that it comes when I am making a quicker stop.. like at a yellow light but I don't recall it happening at say a stop sign. Flying along on a highway and then making a turn?

Sorta feels like this... BRRRRT.... BRRRRT...BRRRRT. Like when you were a kid and used a clothespin to attach a card on your bike wheels to make that cool sound. I don't literally hear anything... Feels like gravel clicking up under my feet. I am always afraid it's not going to stop or something. Is this bad brakes? I had it do this a few times MONTHS ago and then nothing for many months. I thought it might have been from not having the clutch fully engaged but I realized that I had it in N anyway..so???

Feels like a spinning and/or grinding under my brake foot. Might only happen one time in the course of a days driving, or not for a long time (months)between episodes.

Thanks.