Given that \( (x - 2) \) is a factor of \( px^2 - x - 6 \), we can use the factor theorem. According to the factor theorem, if \( (x - 2) \) is a factor, then substituting \( x = 2 \) into the equation should make the expression equal to zero.
Substitute \( x = 2 \) into the equation \( px^2 - x - 6 \):
\[
p(2)^2 - 2 - 6 = 0.
\]
This simplifies to:
\[
4p - 2 - 6 = 0 \quad \Rightarrow \quad 4p - 8 = 0 \quad \Rightarrow \quad 4p = 8 \quad \Rightarrow \quad p = 2.
\]
Thus, the value of \( p \) is \( \boxed{2} \).