Hey Scotty, Big Fan, big big fan. thank you for what you do. i apologize in advance for the long post, and understand if you don't have time to delve into it.   

I have a problem with my 2005 f-150 5.4 3v.  It has 216000 miles on it.  about 2 years ago exactly, at approx 195,000 miles I redid the timing chain kit and new cam phasers with genuine OEM parts and upgraded to a high volume oil pump.  

I haven't had any problems out of her until about a month and a half ago, I was cruising at 40 mph and experienced a lack of throttle response/stall when attempting to maintain speed.  At stop the truck began to idle poorly/wobble.  I pulled over and unplugged the electrical connector to the vct solenoids on each bank, thinking the cam phasers were locking out. at this time i also pulled a code with my scanner for a misfire on cylinder 3, and also o2 sensor 1 bank 1 stuck open/rich.  Unplugging the vcts had no effect and I limped on home about 3 miles and parked her, she was just running poorly.

At that point i pulled codes again and got random/multiple misfires code, and misfire on cylinder 2,3, and 4, along with o2 sensor 1 bank 1 stuck open/rich.  

I replaced that spark plug #3, and also all the coil on plugs.  That didn't fix it.  

Next, don't ask my why, I decided to replace the rocker arms/roller followers and lash adjusters/lifters.  i soaked them all in oil over night. when I put everything back together poured half a bottle of thick lucas engine oil assembly lube all over the cams and valve train components inside the valve covers.

Now I'm getting bank 1 rich and bank 2 lean codes and the associated o2 sensor codes bank 1 stuck open rich, and bank 2 stuck closed lean.  Also i got a code for bank 2 cam shaft being advanced, and bank 1 being retarded. 

I noticed on scan tool data i was only reading 9 hg of vacuum and determined i had a vacuum leak.  I couldn't find it with the smoke method or spraying carb cleaner.  I deduced that it was probably an intake manifold gasket leak in the "engine valley" behind the  alternator  on the inner sides of the intake manifold.  I replaced the intake manifold gasket and on an actual analog vacuum gauge now i am gettin about 15 hg of vacuum, which is still not enough. 

My short term fuel trims are reading -20% bank 1 and 55% bank 2. 

the truck starts, runs ok for about 1 minute idling, then falls down to a sputter but stays on, miraculously.

this past time I turned it on and was just letting it run it started making a tapping noise, but i couldn't catch it with my stethoscope coming from under either of the valve train covers, so i suspect it was either coming from front of engine timing comoponents or deep within the engine like down in the block. and i started get white smoke coming out of tail pipe.  

i've replaced fuel filter, maf, fuel injectors, coil packs, o2 sensor 1 bank 1 and spark plug #3 and the other spark plugs have been replaced within the past 15k miles.  I am prepared to put a new engine in this thing. but would rather try to pinpoint the problem if possible.  I am about to change the egr and o2 sensor 1 bank 2.  

what could cause rich on one bank and lean on the other? do you think this thing jumped time, or that there is catastrophic engine failure inside like bent or broke rods bad valves or pistons/loss of compression? 

just tell me to quit and put in the new $3350 engine if i need too.