I have a 5.3 in my 04 silverado. Has a 148k miles on it, just switched to synthetic oil 5k miles ago and yesterday when I started it to let it run for a while since it's been on jack stands for a month.... I heard a real bad ticking from it. And my knock sensor(s) have been out for ~50k miles.... if I swap them is there a chance it will correct the ticking? Or is it too late at this point and am I looking at an engine rebuild???