ok i have a 2005 f150 fx4 5.4l and its showing P0012 in MEMORY codes only. I clear it and itll stay off for a while and eventually the CEL will come on and itll be in memory again. ive changed the cam sensor and the VTC solenoid on the passenger side which is bank 1? and the truck runs fine other than a little bog when you step on it from a dead stop. cannot figure out what is causing the code to come up and i cannot find anyone online with a similar issue so i hope someone on here can help me. thanks in advance.

 

Has any timing chain work been done?