DIAGNOSIS The electronic variable speed trigger or the motor control board is failing. It is not delivering full amperage to the motor.
FIX First, rule out the battery. Test with a known-good, fully charged 12V Max battery. If problem remains, the issue is internal. The trigger/switch assembly (part 2 607 001 020) is the most common point of failure for power loss.
IF THAT DIDN'T WORK The motor armature could have shorted windings. Check for a burning smell from the motor vents. A shorted armature (part 2 607 001 019) will cause severe power loss and heat.
HEADS UP This tool has a 20+1 clutch. Make sure you are not in a low clutch setting (1-5). For drilling/driving, use the drill bit icon setting or the highest clutch setting (20).