Starting Problem Need Help!

I have a 1986 Oldsmobile Delta 88 RB with a 3.8 L Engine. I have changed out the camshaft position sensor, the cranksaft position sensor, timing chain, plugs, wires, computer, icm, coil pack. It will crank and run for like 15 seconds then cuts off. I pulled the plugs and after one crank it turned the 2nd and 5th plug black. Can anyone help please!

Welcome to AF! This may be a fuel pressure problem rather than an ignition issue. Check the fuel pressure at the fuel rail and see what it is. If it is less than 45 lbs then either the regulator, fuel pump or fuel pump relay may be at fault. Start by changing the fuel pump relay then the regulator and finally the fuel pump.

If the pressure is good with the fuel pump on then start the car and check the pressure I suspect you will get a major fuel pressure drop. That is why the car won't run.