1998 Dodge Truck COMPUTER?

I HAVE A 1998 DODGE RAM 2500 4X4. I WAS DRIVING AND ALL OF A SUDDEN LOST POWER. IT WOULD START BUT HAD MORE POWER AT AN IDLE THAN WHEN YOU GAVE IT GAS. WE CHANGED SPARK PLUGS AND FOUND FIVE OF THEM DETONATED AS IF FROM FIRING TOO EARLY. WE REPLACED THE PLUGS AND TRIED TO GET IT RUNNING LONG ENOUGH TO GET A READING ON THE SCAN TOOL BUT IT JUST WON'T DO IT. I HAVE SPARK BUT IT LOOKS A LITTLE WEAK. ACCORDING TO THE BOOK MY FUEL PRESSURE AND INJECTORS ARE GOOD AND WORKING PROPERLY. IS THIS THE DISTRIBUTER OR A COMPUTER PROBLEM ; OR SOMETHING ELSE?