I have had similar symptoms, and exact symptoms the same throughout the years (never plugged in a code reader). It has always been one of 2 things. Battery is going, or one of the terminal clamps is loose. I hope this is your issue, because the fix is easy. The terminal not being tight is a free, easy fix, but also, my Titan from brand new ate a battery like clockwork every year and a half until I set up a dual battery system. Look to the easy stuff first, and if possible, upgrade the 'coat hangar' factory terminal clamps to solid ones. Not expensive at all.
Hope it helps
Hope it helps