Losing power when driving uphill?

This is generally one of three things either the catalytic converter is becoming clogged, the fuel pump is getting weak, or you need to replace the MAF sensor. Can I ask if you have a check engine light on? If so, we should run the codes.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

I have seen a bad MAF sensor cause this, and it is easy to replace here is the location so you can check it out. When this sensor starts to go bad it will cause low engine power without triggering a check engine light.

Please go over this guide as well:

https://www.2carpros.com/articles/engine-has-low-power-output

Check out the images (below). Please let us know what happens.

There's no check engine light on. How would you know if the sensor is bad?

You need a scanner that can see the Grams per second and then compare it to a new sensor. This is why mechanics have spare parts in their tool box they can just plug in to test. I can tell you the MAF sensor is anormal service item after about 70,000 miles.