My 98 Cherokee is loosing fuel pressure. When it is at full operating temp if will either shut itself off or kick back up and idle fine. If it kicks back up it will keep doing the little process of starting to shut off , kicks back up, idle levels out and starts over and eventually it will just shut off. I put a fuel pressure Gage on it will it was doing this and it drops from 50 to 20 psi. What could it be? I got another fuel pump to put in it today.

 

Pressure regulator in the pump may be bad or a hole in the discharge line in the tank, assuming you're not dumping fuel on the ground, or maybe the pump motor is going south. Hard to say for sure without looking at it but one things for certain: I'd start by replacing the pump.

 

 

Replace that pump assembly and that will likely resolve it.

Don't use an Airtex. No lack of problems with that brand of pump.

My favorite brand of fuel pump is Bosch. Best in the business and worth the extra cost.