Does anyone know the K&N part number for the air filter that fits the 2001 L ?
I went to their website and typed in the vehicle information and the search failed to identify a filter.

 

If you look under macromotive.com, they show KNE-33-2140-1
as the filter that will fit the 01 Lightning.

I just entered my vehicle has a 2001 F-150 and selected the panel style filter. At the bottom it indicates it will fit the 5.4.

 

Read the fine print of the search field entries. Instead of F-150 or Lighting put in "pickup". Check to be sure but I suspect the part # is 33-2140-1.

 

Read through the posts and you will get the feeling that most folks believe you should get the whole kit, not just the filter. I'm not that knowledgeable so I have no valid opinion other than thinking that the air filter alone is probably some improvement, however small.