Po316 And Po307

I have a 2003 Expedition with the 5.4 V8 and it has 90,000 miles on it. I started it up today and started driving down the road and noticed it was running rough. Shortly there after I got a blinking "service engine soon" and it was running like crap. Went home to watch a game and then went back to the Expedition. When I started it again the "service engine soon" light was on solid and it was running very rough. I then took it directly to Autozone to have the codes scanned. The codes were PO316 and PO307. Anyone have any info on what could be causing problem? Could it be as simple as installing new wires and plugs (they have never been replaced)??? Any help would greatly be appreciated. By the way, this vehicle had aways ran perfectly. Three weeks ago I drove it from Buffalo to Tampa and back and it ran like a top and got around 18 mpg. All factory maintenance has been done on schedule since day one.

I would start with replacing the plugs and number 7 coil. Be careful on changing the plugs. The P0307 is a misfire on number 7 cylinder. The P0316 idsmisfire detected in first 1000 revolutions.

Thanks