PSPICE errors when capacitors are 0Farads
Recall the equation for the impedance of a capacitor:

$$Z_C = \dfrac{1}{j\omega C} $$

Now, division by zero is undefined so setting the capacitance C=0 should cause the circuit simulator to complain.

In addition, in the time domain, voltage across a capacitor is proportional to the time integral of the current.  What is the constant of proportionality?

$$\dfrac{1}{C} $$

Once again, division by zero results by setting C=0.

Conceptually though, a capacitor with zero capacitance is effectively an open circuit.