3800 motor issue

[Jonny pontiac]

😫 my 3.8 motor in my Bonneville ran fine, parked it in the garage, went out the next morning to go to work, tried to fire it up. It started hard but started. Ran horribly, very rough, popping, sputtering, blowing black smoke through exhaust. Has gotten progressively worse. Won't start. I replaced coil packs and ignition module. Same results. New plugs and wires, same results. Fuel pressure is normal. Don't know what else to do.