P0303 code 2012 ford expedition 120k miles

Hello, it's a misfire of cylinder 3 that is being noted. This is most likely due to a spark plug or coil or coil boot issue. I'd recommend replacing all 8 plugs and all 8 coil boots, and perhaps #3 coil. Then recheck operation. If the concern remains -- using FORD PARTS ONLY FROM A DEALERSHIP -- then perform further testing, such as a base engine compression and cylinder leak down test. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops