Makes a rubbing noise when I press the gas pedal.

Gotta be a lot more detailed than that. Do you mean there's a constant noise from the engine as long as you hold the gas pedal down? Do you mean the pedal makes the sound only while you're moving it? Cars and trucks make all kinds of noises. Some are normal, some are not. You know no one is going to know where to start without a description and some clues and observations.

There is a tool you might be able to borrow or rent from an auto parts store that borrows them called the "Chassis Ear". It is a set of six microphones, a switch box, and headphones. You clip the microphones to suspect points, then drive around while listening with the headphones. You can move the microphones around to zero in on the source of the noise. Be aware that many mechanics have never seen or even heard of this tool. Suspension and alignment mechanics use it to find rattles, squeaks, and other noises.