underdog

Don't mean to sound ignorant but what does the abbreviation (FI) stand for? See it all the time in the threads but don't understand what it is refering to. I thought it meant fuel injected but that is what the 4.6 is since it does not have a carb on it. Just wondering.

mustanghobby

It means forced induction, aka. supercharger or turbo.

Burnsy

and you might also be wondering, NA, means naturally aspirated, or no supercharger, the air is natural, and not forced in