I just bought a 1998 Chevy 1500 Z71 with the 350, 4x4, Auto Trans.. and driving home from work this morning, it was doin some weird stuff. I was goin down the road and set the cruise at like 50-55, and I noticed every 5 seconds or so the motor would rev itself up like somewhere around 2-400 rpms. It was cruisin at around 1500 rpm. I figured maybe it was because I had cruise on and I was going up a hill or something. So I took my cruise off, and it still did it.. the whole way home. It kinda seemed like the faster I was going, the more it did it. Also, another problem its got it, I noticed sitting in my drive way, with the truck running in park, when I hit the brake.. it clicked really loud. I know it would be like the button/sensor or whatever it is for the brakes to come on.. but why would it be so loud? Any imput is greatly appreciated!