lol..guess hes real lucky!!....j/k....you make it sound like i only offer my help to a select few
but seriously, i do my best to catch every thread but this forum has gotten so big that that would be a fulltime job, i catch as many as i possibly can though.....
ANYWYAS, back to the topic, YES, filters that come with a cap dont tend to seal well, and the whole purpose of them coming with the cap is to get you to take off the factory cap, hopefully lose it, and be stuck with the aftermarket from then on. I know a lot of guys use puralators in thier truck cause they are cheap, but they are not good filters. There is a reason they are so cheap. When injectors are approz 350 bucks a piece, IMO you put the best possible filter in the truck to protect those injectors.
The aftermarket filters that come with a cap do tend to leak, and while i dont have any specific knoledge as to why, my assumption is as was said above, its overall filter height keeping the lid from sealing. It could also be a poor quality o ring as well. Either way, using the factory cap that seals properly with whatever filter you can get that fits, perferable motocraft IMO, is your best bet!!!!