Ford Expedition 01 Eddie Bauer 2 x 4 v8 4.6l 56K miles

"Sputters" on the interstate when trying to gently acellerate from 60 to 65 or 70 on the interstate. I'm not a lead foot but to stop the sputtering and jerking I have to floor it.   I've been good about keeping all fluids changed and am an old fart so I don't run it hard. Got it checked on a diagnostic machine and it said "pass." Could it be dirty fuel filter or shall I start to worry about something major. Any inmput? My car is a Saab, and I've repaired blower motor, heater core, waterpump and tensioner pully so I can get the "a do-it-yourselfer can do this job" DIY jobs done. Any advice or "quirks" regarding this year of this engine of this ford with this symptom would greatly be appreciated. Thank you so much.

Optional Information:
2001 Ford expedition v8 4.3liter

Already Tried:
tried getting off the old fuel filter but couldnt!! (I'm so ashamed, thought it would be simple like my old Honda '81 accord would be!! THANKS