I went to get spark plugs for my '95 Ranger 3.0 L and O'Reilly Auto asked if it was a TFI ignition or a EDIS ignition. They had no clue what that meant or how to determine which it is. They each use different plugs. Anybody know how to tell?

 

Should be EDIS, meaning that there is a coil pack and no distributor.

 

Why should that matter in what kind of spark plugs you need? arent they they same plugs on each ignition system?

 

Your truck lists either ignition, there must have been some with a distributor and a TFI module and some with EDIS, (Electronic Distributorless Ignition System). The plugs listed are different for each type.
For TFI Ford lists: AWSF32P and for EDIS Ford lists: AGSF32FM
Both are Motorcraft plug numbers and original equipment.

I think the difference is that there were still a few early non OBDII trucks sold in '95, I had one myself. But either mid year or only in some areas, they went to the newer design and OBDII.

 

So it only matters because he's got a 95 and they used two different plugs for the two different ignition systems?