2006 Dodge Durango Hemi 5.7

So on the way to Tampa from the mountains of NE Georgia, I noticed when I got off the interstate for gas, stopped at a light, in drive with the footbrake on, there is a significant vibration. Shift it into neutral or park and the vibration goes away. Shift into any gear, and it returns. Soon as you release the brake and allow it to go, vibration is gone. It ONLY does this when stopped, in gear with the foot brake on.

Then, after returning to interstate speeds, I noticed that when I accelerate ( or a load condition ) that it feels sluggish, rough, lacking the usual very smooth ( and fast ) acceleration, like it's struggling, and it SHAKES; I'm almost tempted to say it feels like it's missing, or the fuel-mixture is off. But as soon as you back off on the gas to cruising speed ( no load ), it's fine.

Now here's the kicker - it's not throwing any codes. No P-Codes, nada, except 4 codes relating to an unrelated other issue ( why are BOTH my Passenger and Driver Air-Bag lights on ). Those codes are: B1BA6, B1BA8, and B223D )

Now it IS throwing an unknown code, U1415, Implausible/ Missing Vehicle Configuration Data, yet I have scoured the web, including this forum, and have read it ( U1415) refers to the tranny, the O2 sensor, the ORC, it's this, it's that; can't seem to get the same answer twice as to what this code is....but I digress as I do not believe it is related to the above issues.

Anyway, (1) anyone got any ideas about the oddity in how it's acting when stopped in drive, and under acceleration/load, and (2) what in the Bloody Pit of Hades does U1415 mean???

TIA