shaking

I recently purchased a 2020 wrx limited and on on occasion when I stop at a light my engines rpm will drop down to around 250 while the car shakes left to right and bounce between 300 and 700 for 10-ish seconds before returning to normal. Any ideas of what might be causing it/what I could be...

Hi, I have an Automatic 2002 Impreza 2.5RS. I have had a lot of work done to the car in the last year, just to keep it going. It has 149,000m. The car is shaking violently at times ONLY with acceleration, and ONLY over 40mph. The worst speeds are around 55-70mph, but it evens out before or...