Missing under load

Couple of things to look for,
I have seen crank sensor signals breaking up that feel like it is starving for fuel.

Also if the distributor was removed it needs to have sync set with a scan tool.
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1.Connect DRB scan tool to data link connector. The data link connector is located in passenger compartment, below and to left of steering column.
2.Gain access to SET SYNC screen on DRB.
3.Follow directions on DRB screen and start engine. Bring to operating temperature (engine must be in “closed loop” mode).
4.With engine running at idle speed, the words IN RANGE should appear on screen along with 0°. This indicates correct distributor position.
5.If a plus (+) or a minus (-) is displayed next to degree number, and/or the degree displayed is not zero, loosen but do not remove distributor holddown clamp bolt. Rotate distributor until IN RANGE appears on screen. Continue to rotate distributor until achieving as close to 0° as possible. After adjustment, tighten clamp bolt to 22.5 N·m (200 in. lbs.) torque.
The degree scale on SET SYNC screen of DRB is referring to fuel synchronization only. It is not referring to ignition timing. Because of this, do not attempt to adjust ignition timing using this method. Rotating distributor will have no effect on ignition timing. All ignition timing values are controlled by Powertrain Control Module (PCM).



As mentioned fuel volume and pressure need to be correct( 49.2 psi +/- 2 psi), with a high rpm misfire it could be running out of fuel. Run it with a gauge to make sure it doesn't loose fuel pressure when acting up
.On a 2002 Durango fuel system it has a in- tank fuel module,the fuel pump module containing the electric fuel pump, fuel filter/fuel pressure regulator, fuel gauge sending unit (fuel level sensor) and a separate fuel filter located at bottom of pump module.
There isn't a vacuum sensed regulator with a return line like a lot of engines have, just a single line from the module.
Not sure what you are using for fuel pump/regulation.