Check the coax cables first (if you have RV-58 with screw on connectors they almost always start as a culprit), next check all the jacks to ensure they are still insulated from the panel, check the wiring on the jacks (specifically the MIC jack) and then the wiring from the PTT to the jacks.
Typically if it's a gremlin type of an issue, one of the above is the cause.
Cheers,
Stein