It is in the fuel tank.
Located in the fuel tank.
The fuel pump in the 1998 Plymouth neon is located inside the gas tank.
The filter is located in the pump, on the gas tank.
the fuel filter is located on top of the gas tank.
It is above the inboard side of the fuel tank.
Underneath the car near the gas tank on the passenger side.
I believe 12.5 Gallons, that's what my 2000 Plymouth Neon LX has, which is basically the same and I certain they would have the same size fuel tanks.
Bad fuel filter
The regulator is part of the fuel pump assembly located in the fuel tank.
Plymouth does not use inertia/reset switches.