Is it normal that my right foot feels a slight vibration when I lightly press the gas pedal?

is the engine on or off?

 

It is hard to say, but I'm going to say anxiety-induced concern, unless you can come up with something more objective than what you described.

 

Try checking rotor thickness and runout?

 

Does it do this with the car completely off? The moving part of the gas pedal mechanism might need lubrication. Not that I have ever heard of this being a problem on a Prius, but in general if a piece of metal has a hinge or a bearing it is possible for it to stick when it moves, which can be perceived as a vibration. That it doesn't happen with "more force" would be consistent with that, since a little bit of sticking is easily overcome with a lot of force.

 

The gas pedal is not mechanically linked to the engine, only linked by electrical wires... So any vibration you're experiencing isn't coming from the pedal but from somewhere else. Recommended fix in this situation is feeding your mind more important things to be concerned about than how reliable one of the reliable cars ever made really is. Subtle vibrations or hard to replicate noises a customer is concerned about when their car is already 16 years old is too often a red flag that its the kind of customer you're better off avoiding doing business with because they'll create all kinds of needless hassles and worries that aren't anything worth worrying about.

 

Sure, but it is mechanically linked to the vehicle. I was suggesting that sticking in that linkage might be perceived as vibration. If it isn't sticking doing it then whatever is vibrating is being transmitted along that linkage. If it was just a general vibration (like a tire out of balance) the OP should feel it by putting a foot on the brake pedal, with no pressure, too.

 

In other words, where do you really think those weird vibes are coming from?