Noise I can’t explain?

What is your question?

Just this morning my car made a really loud, weird noise a few times while I was driving and it freaked me out. It almost sounded like the engine was trying really hard, it got really loud and then softened back down to normal again. This happened a few times when I was stopped at a light or just while I was driving. My battery is probably a year new and I know it’s been checked when I get oil changes so I don’t think it’s anything to do with that. I also didn’t notice anything wrong when I lifted my hood and checked. When I got to my destination I turned my car off and let it sit for a second, then on, let it sit, and drove back home and it didn’t make the noise again. My roommate thinks it’s because the car was sitting for a few days but I can’t see why it’d make that noise just because of that.

How long has your 2005 Toyota Sienna had this problem?

10 mins in the early morning