I'm looking at an 04 with a 5.4 that runs really rough with no power. The seller says it had a few codes. He didn't know the numbers, just the problems. He was told cyl 1-4 misfire, cam sensor, and o2 sensor. Could these point to an actual motor issue or more likely a sensor or computer issue?

 

You list no mileage or any maintenance history. Cyl 1-4 is one whole side of the motor, shooting from the hip I'd wonder if there's a head gasket out.

 

Very likely timing chains / guides / tensioners and cam phasers . But that's not the end of the world (~ $1,500.00 if you are up to doing it yourself). Potentially a deal there if the owner has heard all the negative (B/S) horror stories about 5.4s.

 

That is about all I know about it. Milage is around 130 k. From what he said it stsrted out of the blue with no prior noises.

 

I did both sides of mine for about $1,200 including buying the tools.

but, with the misfires, cam sensor code, and O2 sensor code, I'd lean towards phaser or jumped timing. That's the simplest issue that could take out the whole side of a motor. With a head gasket, I'd expect to see no cam timing code, and misfires on one or two cylinders...