So when I got my Tundra, the PPI mentioned that it was likely the rear drums we’re original to the twelve year, 230k mile truck. I finally took it in to have them replaced. They replaced drums, shoes, and cylinders, as well as flush and bleed the lines. It came back with longer pedal travel, and is noticeably quicker from a standstill.
Theory? One of the brakes was rusted in some degree of engagement, limiting pedal travel and holding the truck back. Never thought a brake job would make the thing quicker!