I have a 2011 F150 XLT 5.0 SCREW Cab 4x4. Just turned 75k miles. My injectors tick, too. Very common. Use a tube of some kind kind and move it around the fuel rails while listening. Some injectors maybe louder than others. Mine are, can feel the ticking when touching each injector. Remove your pvc valve, shake it. The ball inside should move freely. I removed and cleaned mine with brake cleaner, air compressed it. Be surprised the oil residue in it.