Ramps 1.4 Bigger motor

Hey, I have an arduino mega and a ramps 1.4 shield for my custom 3d printer. My problem is that a standard nema 17 motor is not strong enough to move my Z axis. I have been doing some research on attaching a bigger motor but I am confused about what I need. I have two nema 23 motors each take 3A but my ramps board only does 2A per coil but I dont know what that means and cant find anything. Please help me out with what I need to do to make this work and thank you so much.

You could change the z-axis gearing by using a smaller pitch rod ( if you have any ) or connect an external driver with jumper wires where the z-driver was placed.

my rod is already a 2mm pitch rod, and I am not really sure how to connect an external driver. I have seen a few things about gearboxes, is this something that would work on my smaller motors?

Your going to have to use external stepper drivers that can provide 3 amps

Ie remove the pololu module, make up a pin header so you can get at the Step,Direction, Enable and GND pin and wire those as need to the external stepper module

It seems rather strange that the motors of your Z-axis should be too weak, as these are usually the ones needing the least power to fulfill their task. Does your printer have some particular construction which requires so much strength on the Z-axis?

When the Z-motors are giving problems, it is usually not a problem of motor strength, but more often it is due to the too high default settings for speed and acceleration of the Z-axis...