2004 5.4 won't start
 

Wife came home complaining that her 2004 Expedition 5.4 was acting sluggest. Next day it wouldn't start. It was turning over very slowly. Checked battery, very low. It was 6 1/2 years old so I replaced, thinking that the starter was pulling the voltage down so low, that the computer would not work. Still, no start. Checked for DTC, none. Checked fuel pressure. Got 35psi. Could it be camshaft or crankshaft sensor, even though there are no codes?
Any ideas?