After 126000 miles I decided to put new plugs in my 02 SuperCrew with a 4.6 in it. That was a royal pain. I got all 8 plugs changed out with new Motorcraft plugs. When I started it up it is making an awful noise almost like a rod knocking or something and the exhaust has a much stronger odor than it did before. I have changed plugs my vehicles plenty of times before and never had anything like this. Any help would be appreciated.

 

Go back and check your work. Make sure everythings tight and connected properly.

 

Thats my next step for this morning. Then I am going to take it and see if it throwing any codes.

 

Took the new plugs out and put the old ones back in and the noise was a little quieter but still there. Not throwing any codes but has a runs extremely rough like it is not firing on a couple of cylinders. Not sure which way to turn now other that to take it to a mechanic and see what went wrong. Is it possible that it could have messed up a rod or something?

 

are all the c.o.p proplery pluged in? did you crack any of the rubber boots? is it posible that you pluged the wrong wires into the wrong coil? just some ideas.
are you sure that the plugs are not to deep in the head (are thay the same plugs).