I have a 1996 Blazer with 218000+ miles on it. Purchased 2yrs ago from transmission mech. I shifts hard into 2nd then is okay. Under all types of conditions I have noticed that it has a hard clunk, skip, knock, whatever you want to call it between 50-60mph. I have had it coded at a parts store and they said I have a random misfire. I believe mine to be a transmission problem. I am having trouble with the trouble shooting, I can usually do the repair work. This is my daily driver and other than this issue it still runs great with about 21mpg. any thoughts?