I undertook the job of replacing my spark plugs. They didnt break. All seemed to go well,until i crunk my truck. It now is knocking hard,almost sounds like a rod. I know this cant be it. Could multiple coils have went bad? I'm just a shade tree mech...Some help would be VERY GREATLY APPRECIATED..

 

The 97-03 plugs aren't at issue, it's the 04-08 plugs that are the problem. What size is your engine? Are you sure you torqued them to at least 28lbs? The 13lbs stated in the manual will not hack it. Do you have COP's or coil packs. If you have the COP's did you get them back on and fastened down correctly? Just did my 5.4 last month. Has the SES light come on? If so what code/s is it showing?