After LOTS of testing, I have come to the conclusion that my AC keeps cutting off because the blower motor is overheating. There are no blockages and the coil is as clean as a whistle. I grabbed my multimeter and tested the voltages at the wires, and here's what it read:
blk wire - motor on: 105.5v, off: 121.8v
red wire - motor on: 175.5v, off: 121.8v
yel wire - motor on: 121.1v, off: 121.8v
blu wire - motor on: 120.9v, off: 121.8v
Do all of these seem normal? Will the motor and capacitor need replacing? Is there anything else I need to test?