In order to debug your printer:
1) Make sure that all axis (X,Y,Z,E) move freely with the power off.
2) Check each of them over the entire range
3) Make sure that the set screws on all gears are tight
4) Make sure that the belts are all tight
5) Get the current spec data on your motors from the people who sold them to you
6) Grab a DVM and set the drive current to ½ the spec on the X and Y
7) Set the current to the spec on Z (two motors, each get ½)
8) Configure configuration.h in Marlin so it matches your printer
9) Compile and upload your version of Marlin with the Arduino IDE
10) Connect with Pronterface and make sure the proper stuff comes back at connect
11) Try moving each axis one at a time, check for:
a. Proper direction
b. Proper distance
c. Return to start
12) Try to zero each axis one at a time, check for:
a. Proper direction
b. Proper stop point
Once you have that part done, you can begin to evaluate how much current your motors likely need.