No high end power

Hello, Dave here, contributing to RepairPal and providing expert advice since 2010. How many miles on your Expedition? Any recent repairs? Engine performance maintenance? The hard part with a 20 year old vehicle is not knowing a darn thing about what it's been through! I can give all kinds of speculation on what could be happening, but there are so many areas to touch on. Without any kind of understanding as of what might have been in its past, it's really hard to know what to make a recommendation for. My initial thoughts are: have the coils and spark plugs ever been replaced? With genuine Ford parts? Has anyone checked engine compression pressures for all 8 cylinders? Can we confirm there is no exhaust restriction or air intake restriction? Those are opening questions. For more detailed understanding of what's going on, you'll need to engage with a local shop near you. https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.