2001 Ford Ranger Question: HELP!! FORD IS DEING

MY 2001 FORD RANGR XLT HAS BEEN ACTING UP LATLY AT FIRST I THOUGHT THE OIL BUT PUT OIL IN IN TODAY AS I WAS PULLING IN TO MY SCHOOLS PARKING LOT IT JUST SHUT OFF ON ME I HAV A BRAND NEW BATTERY IN IT NOW I HAVE A REALLY LOUD RATTLING NOISE THAT SOUNDS LIKE THE FAN BUT COULD BE THE ENGINE. I HAVE NO CLUE WHAT COULD BE THE PROBLEM I HAVE BEEN UNDER NEATH THE HOOD. WHEN I ACCELERATE IT KINDA SOUNDS LIKE A GO KART MOTOR ITS REALLY LOUD PLEASE HELP I HAVE NO MONEY OR IDEA WHAT COULD POSSIBLY BE WRONG