2013 BMW X5 SAV Power Train Problems

HELLO, MY NAME IS [XXX]. I AM 77 YEARS OLD MAN AND MORE THAN 50 YEARS DRIVING EXPERIENCE. I BOUGHT BMW X5 OCTOBER 2013 FROM TENAFLY BMW DEALERSHIP. THIS CAR WAS MY LIFETIME DREAMED CAR. LIKE A BMW SALES SLOGAN ?ULTIMATE DRIVING MACHINE? I WOULD LIKE TO HAVE AN EXPERIENCE BMW CAR'S JOY OF DRIVING. BUT AFTER FEW MONTH LATER I WAS DISAPPOINTED TO HAVE BMW X5. WHEN I DRIVE TO ACCELERATE PUSH THE GAS CAR DOSE NOT RESPOND AS QUICKLY AS PUSHING GAS. SO I TOLD THE MECHANIC MY PROBLEM THEY DID SOFTWARE UPGRADE. AFTER SOFTWARE UPGRADE CAR WAS GOOD RESPONDING DRIVE. BUT FEW WEEKS LATER BACK TO OLD CONDITION. THESE THINGS FOUR MORE TIMES I DID. COULD YOU POSSIBLY HELP ME OUT OF THESE PROBLEMS AND MY FRUSTRATION? HERE ARE MY PROBLEMS: 1. SLUGGISH AND HESITATING RUNNING WHEN ACCELERATION 2. BETWEEN TRANSMISSION AND GASOLINE SENSOR PROBLEM?!(I THINK) 3....