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 suspension, some JKS stuff, 33x12.50 Goodyear MTR's w/Kevlar, 15x8 Pacer wheels, thedirtworx rear tire carrier