Re: my 2000 jeep grand cherokee
Welcome to the garage.
Your jeep is a WJ, so better to put your questions overthere.
You did change many of the components already. Did you measure the fuel pressure at the rail? If that is ok, i would suspect the MAP sensor. This is the number one factor for the PCM to calculate the injector pulse.
If you have a scanner which shows live data (or android phone with Torque app and bluetooth dongle), you can check the MAP with engine off (ignition on) and compare to the local atmosferic pressure. You could try cleaning the MAP first and see if that makes any difference.