I have a 1999 Cherokee. 4.0 engine. Is the fuel regulator located inside the tank? Thanks and Happy Holiday..

 

I wouldn't consider myself an expert on the subject but I have installed several fuel pumps. The xj has no external regulator, its a part of or a function of the pump. As a general rule if your getting less than 49 psi at idle or it drastically drops under wide open throttle you need a new pump.
A really common failure point on these fuel pumps is the check valve. After shutting the engine off the pressure bleeds off back into the tank causing slow starts and longer cranking times. My solution is a fuel pump prime button on the center console.