Just bought a 1995 silverado from a tow yard on a lien sale yesterday. Probably a bad idea given the fact that I know nothing about the history of the truck and it seemed fine at first but by time I got home I was hearing a loud ticking or knocking sound only over 40mph and over 2k rpms. Only only while on throttle. Goes away when I let off and I even put it in neutral at 55 and held rpms at 2500 just to see if it was there because I wouldn't hear it while idling at all. No idea what it could be. Worried I just wasted my money if it's internal engine problems. I'm good with mechanical stuff but not the best at diagnosing.