Are the top and bottom O rings on the 2001 5.4 fuel injectors the same size?

Maybe just my eyesight but the manifold end looks a little smaller.

 

yep, they're the same size. just swapped them all out a week ago on mine. although, mines a 2000 but they're both 2v engines so they have the same injectors.

i think they just shrink a bit over time from heat, so just put the new ones on and coat them with some fresh motor oil to make em slide in a lil better and you should be good.

 

yep same size. replace them all if you pull them out.