Working on my 2005 f250 5.4L 3v.

Engine runs fine, revs up and sounds good. It has a slight miss when under acceleration. When I return from a drive the engine will stall as I coast into the driveway with the clutch pressed. When I start it back up the engine will thrash around and start the loud ticking from the pass side. I can give it fuel and rev up to around 1500 rpms and hold for a few seconds and the engine smooths out and returns to normal. I can make the engine go into this "thrashing" state by just turning the truck in the driveway. It seems that whenever the engine lugs that it has trouble recovering. I have just changed the timing chains and tensioners so I am sure it is nothing with that end. I do get the P0012 code and I am starting to suspect the phaser. I switched the vct solenoids around and the problem stayed with bank 1. I also tried driving the truck with both vct solenoids disconnected; It ran like crap but no stalling or thrashing. Would these be accurate tests to determine if the phaser is bad? Is there anything else that may cause this problem? Thanks