What is the fuel pressure need to be on a 87 jeep cherokee straight 6

did you change the fuel filter, very common problem that gets over looked too many times

Do compression test first. Have you got a blocked air intake? Sometimes people put a rag over the intake tube inlet when blowing outthe air box & forget it & it gets sucked in & blocks airflow. The things I think of are straight away are Spark, Fuel, Fuel pressure, Air, Timeing, Compression

it's under the throttle body

Fig. Fig. 1: TBI fuel pressure regulator

1. Remove the throttle body assembly from the vehicle as outlined in this section.

WARNING To prevent spring pressure release, hold the regulator housing against the throttle body while removing the mounting screws.

1. Remove the three retaining screws that hold the pressure regulator to the fuel body.
2. Disassemble the pressure regulator assembly. Note the location of the components for reassembly. Discard the gasket.

To install:

1. Install a new gasket and the regulator assembly. Tighten the three retaining screws.
2. Install the throttle body assembly as outlined in this section.

WARNING The pressure regulator diaphragm MUST be installed with the vent hole aligned with the vent holes in the throttle body and regulator housing!

the reg is most likely on the fuel rail. perform a pressure test with a fuel pressure gauge. attatch the gauge to the test point on the rail(looks like a vavle stem on the wheel), start engine and measure pressure. you must get the specs for pressure for your vehicle.typicly between 30 and 50 shut the vehicle off and leave the gauge attached. the pressure should hold. is the check engine light on?

Have a fuel pressure test done, that will show if the fuel pump is weak, or the fuel pressure regulator is faulty.

inside the gas tank!

Check the in line fuel filters. Dirt and debris can clog the filter under vacuum pressure from fuel pump and starve the engine. After the car sits and the vacuum is released, the debris falls away from the filter allowing the fuel to pass thru the filter until it clogs up once again. There are also in tank filters but more than likely the culprit is the inline. They are pretty inexpensive and easy to fix.

check air filter change the charcoal canister .scan it to check the map sensor and the vacuum line that goes to it .make sure fuel pressure regulator is working.

The oil pump is in the pan at the bottom of the distributor.

the sending unit is more then likely a mess, take it back to where you bought it and demand they fix the problem