My I6 02 4x4 Trailblazer has started to drop oil pressure under hard braking and will stay at 0 until I give it alittle gas. After I give it alittle gas it will come right back up to normal. It seems I have to be braking pretty hard and the engine has to be warm for it to do it. Also it will not drop until it comes to a complete stop after braking hard. All other times while driving it acts perfectly normal. I've put around 4k miles on it since i've owned it and just did my 2nd oil change to it. I've put 5w 30 Valveline Max Life in it both times and it's at 121k miles now. Also when the pressure gauge drops it doesn't knock or make any kind of noise's what so ever. Any thoughts on what this might be or steps to take to get this resolved?