94 Olds Cutlass flooded with gas

[Brian D]

My 94 Olds Cutlass Supreme 3.1 is now flooding even in the city. Before it was just highway under heavy load. Black smoke billows from the tail pipe and I just have to let off the gas a bit and it clears up and runs fine.
What's happening? Where do I start?
Help me please anyone!
Thanks, Brian

[Slade901]

It could be your Fuel Pressure Regulator failing. The Fuel Pressure Regulator has a diaphragm inside and if that diaphragm ruptures, excess fuel is sucked into the Fuel Pressure Regulator vacuum hose and into the intake. Check the Fuel Pressure Regulator vacuum hose for any sign of fuel inside the vacuum hose (do it after running the engine for a while).

Check your CTS (Coolant Temperature Sensor). If the CTS is bad, either it gives out a too cold signal or too hot signal to the computer.
If it is stuck in too hot, it signals the computer and in turn it will immediately close the fuel injectors and not stay long enough.
If it is stuck in too cold, it signals the computer and in turn it will immediately open the fuel injectors for a long time and probably flood the engine.

Black smoke is usually excess gas. However, it might also contain oil and so the valve seals are worn out and leaking out oil past the valve seals and into the combustion chamber.