This sounds very suspicious to me. Almost like you are having the infamous leaking head gasket failure. Usually the #4 cylinder will misfire, not the #8 though. I would immediately check your coolant level, pull the #8 cylinder plug and look for coolant in the cylinder.
You do NOT want to get the HYDRO LOCK sooo many '97s experience. Run a search for HYDRO LOCK and there will be TONS of information. Blue Oval probably will chime in, as he knows about this problem first, second, third hand, etc., etc.
Also, it takes some driving cycles to throw a misfire code so if you cleared the original code, it may take some miles, start/turn off the truck cycles for it to reappear even though the cylinder is still bunk. I cannot stress enough to check those gaskets!!!!!!!!
Last edited by beowulf; 05-01-2006 at 05:54 PM.