Always check your bolts! (cam sync)
 

So I replaced my camshaft synchronizer and position sensor few months back and had my CEL trip with the same issue. I used a parts store sensor and thought that was the problem so I order a genuine motorcraft one from Ford. Last night I go to remove the sensor and the whole sync rotates left. WTF. So I get the sensor off and feel around the base of the sync, the hold down bolt had backed out at least 1/2"! Thankfully I caught this before anything really bad happened. I don't remember if I torqued that down when I replaced the synchronizer but it is scary to think how close I could have been to losing my engine.

So as a friendly reminder, check, check then check again.