Prius C in the Big Hills - a Question...

I discovered the cause for this with my new 2018 C. The gas pedal is designed to hit the floor when you press the gas pedal all the way down, there is no other stop for the pedal. If you put in a WeatherTech floor mat, which Toyota sells as an accessory, the pedal travel will be limited and the car will feel underpowered especially when climbing long grades or trying to pass. I discovered this when my C would climb steep hills much faster in cruise control than when using the gas pedal.

The underside of the pedal has a plastic pin that is what actually strikes the floor to limit pedal travel. I used a fine tooth hacksaw blade to reach under the pedal and saw a 1/2 inch off of the pin. This immediately doubled the cars power. I can now go up a steep mountain grade easily at 60 mph+ in a car that previously couldn't even manage to climb at 45 mph. These are long steep grades requiring 5 to 8 miles of nonstop climbing. The battery shows no significant discharge while climbing.

 

I go up the Cajon pass daily, which has a 4 mile 6% grade. I try to keep the revs between 3.5 to 4 K. Scotty calls up from the engine room that "she's gonna blow" but I never run out of juice.

 

A throttler controller is a better option and gives you full range of control on depression to output ratio.

 

Maybe just cut out part of your aftermarket floor mat where it's interfering with that pin?

Just don't make a too-small hole that could snag the pin and keep the pedal down.