  We prove the asymptotic formula for the fourth moment of automorphic
$L$-functions of level $p^{\nu}$, where $p$ is a fixed prime number and $\nu
\rightarrow \infty$. This paper is a continuation of work by Rouymi, who
computed asymptotics of the first three moments at prime power level, and a
generalization of results obtained for prime level by Duke, Friedlander &
Iwaniec and Kowalski, Michel & Vanderkam.
