2006 Ford Focus black smoke when pressing the pedal

Hi there,

Black smoke is associated with too much gas reaching your combustion chamber. Your ratio air/fuel is too rich. Your fuel pressure may be too high, or your air filter may completely clogged, or you have one or several leaky fuel injector(s). I'd start by scanning the car for codes (including pending codes). Check your fuel pressure, if abnormally high your fuel pressure regulator could be bad. Also a residual fuel pressure test could confirm a leaky fuel injector. You can also remove a spark plug and check if it's carbon fouled (which would point toward a leaky injector among other things). Check/replace your air filter. Check your coolant sensor and O2 sensor, especially if there's a DTC for it: a bad sensor can prevent your car from going into closed loop when the engine is warm which result in a rich condition.
It is also possible that your ignition system is getting weak which result in your spark plugs and O2 sensor getting fouled.