02 Pontiac Grand am, acceleration issue

So, 02 Grand am only has 86,000 miles on it. Just recently it started kind of rocking back and forth during acceleration. And the rpm gauge wiggles up and down. Usually happens around 45-50 mph and it does it when the gauge is between the 1 and 2. Sounds like a transmission issue to me but just hoping to get some ideas.

I could be wrong but it sounds like an engine misfire or a fuel pump issue. Did you do any work on it before this?No engine CEL?

No check engine light and maintenance is up to date. And there’s no other issues… it’s perfect otherwise. So, it’s just super weird

Also, no prior work. The thermostat was replaced probably 5 months ago but it’s been perfect since until about 1 week or so ago

Bad gas is a possibility. Do you fill up at the same station all the time?

Yes. Always at the same place. I work at a gas station so I always get it there lol.

Do you put gasoline in your car while the tanker is filling the underground tanks?

No. I have never done that.

This car is not known for transmission issues but a lot of intake gasket leaks causing a lot of problems down the road.Here is what I found

Okay. Thank you so much for your help. (: