Fuel pressure reservoir is my guess. They are known for wearing out in TJ's. Nothing wrong with leaving it. Just kinda aggravating. Mine does the same thing. I'll replace it eventually when all the other major mods are done.
OME 2.5" coils and Nitro Shocks, Metalcloak front track bar, JKS Quick discos, 33x12.50 Goodyear MTR's w/Kevlar, 15x8 Pacer wheels, thedirtworx rear tire carrier