Fill the missing value in this series:
C2BA, FE4D, IHG8, ?

Let's break the series into its constituent parts:
1. First Letter: $\text{C}(3)\stackrel{+3}{\to }\text{F}(6)\stackrel{+3}{\to }\text{I}(9)\stackrel{+3}{\to }\text{L}(12)$
2. Number: $2\stackrel{\times 2}{\to }4\stackrel{\times 2}{\to }8\stackrel{\times 2}{\to }16$
3. Remaining Letters: * In $\text{C2BA}$, the remaining letters read backwards form $\text{A, B, C}$.
* In $\text{FE4D}$, they read backwards form $\text{D, E, F}$.
* In $\text{IHG8}$, they read backwards form $\text{G, H, I}$ (arranged as $\text{I, H, G}$).
* For the next term starting with $\text{L}$, the group of letters reading backwards must end at $\text{L}$, which is $\text{J, K, L}$. Arranged in reverse order starting from $\text{L}$, it gives $\text{L, K, J}$.

Combining these elements: $\text{L}+16+\text{KJ}=\text{L16KJ}$.