spark plugs
 

Ok stupid question, this is my first 4.6 and im going to do tune up. but where in the hell are the spark plug's also someone suggested using sea foam what is it. trying to solve detonation problem so i can install juice. help.

Spark plugs are next to the injectors under the fuel rails. Most likely the coil covers say motorcraft still so pull those out and they go into a small shaft and at the bottom are the spark plugs. Sea foam will clean out some carbon build up you may have and may help your detonation problems but I would take out one of your spark plugs and "read" them to see if there are any issues with them first. For more on Sea Foam and how to use it properly there is a tutorial in the "How To" section.