The 4.0-liter, inline-six engine came as standard equipment in the 1998 Jeep Cherokee. Located inside the gas tank, the fuel pump is rated to produce 47 to 51 pounds per square inch. At the fuel rail, after being reduced by the regulator, the pressure should be 31 psi at idle.
Your Grand Cherokee's fuel filter is an integral component of the fuel pressure regulator, mounted on top of the fuel pump module. To replace the filter and regulator assembly, you have to drop the fuel tank, but you don't have to remove the fuel pump module.
Identify your engine by the eighth character -- an "S" -- in the Grand Cherokee's vehicle identification number. This multi-port fuel injected, overhead-valve engine made by Chrysler produced 190 horsepower at 4,750 rpm and 225 foot-pounds of torque at 4,000 rpm. The powertrain control module controls ignition timing and idle speed. These settings cannot be adjusted.
