Slight Rumble/Vibration From Gas Pedal and Floorboard Area After Driving 10-15 Mins or So?

Hello Everyone. I'm new to this forum, but at the beginning of January of this year I finally picked up a 2nd Gen Tacoma. She's a silver 2015 TRD Off-Road DCSB with 130,000 miles and I absolutely love her so far. A few weeks ago I started hearing some chirping from under the hood, which I assume is likely a worn belt or pulley. I'm a college student and was at school when I noticed the chirping noise but now that I'm home for spring break I'm taking the truck to a trusted family-friend mechanic to get the belt/pulley replaced.

A few nights ago, I was driving the truck and noticed that after 10-15 mins or so of driving I started to feel a very modest rumbling/vibration sensation (it does not produce a noise) from the gas pedal/driver's side floorboard area (does not seem to affect the break pedal). Additionally, when I drove home from school for break yesterday (about a 2 hour drive) after about 10-15 mins of driving I felt the sensation again and it persisted the entire way home. The feeling is very, very slight, and to be honest I could just be going crazy since I'm admittedly a little hypersensitive to "noises" and "feelings" the truck makes. That being said, it does feel different from the first 10-15 mins of driving.

Obviously, I'm going to have the mechanic take a look when I get the belt/pulley replaced but I wanted to see if anyone had any ideas regarding this. I've read up on similar issues throughout TW and I've seen potential problems like U-Joint issues, Carrier Bearing stuff, and a rattling Heat Shield. Although I don't think the belt/pulley would cause the vibration issue, could that perhaps be the case? This is the first vehicle I've actually owned and I definitely want to learn the ins-and-outs. Any advice/help would be greatly appreciated! Thanks!