Currently have no clear description, Sister mentioned it had issues when she drove it home.
I have a 2005 Pontiac Vibe fwd automatic with 289,012 miles. what sister told me, Once it shifted into 4th gear the car started shaking violently and rpms went up to 4000 rpm and when she let off the gas it did not go down instantly. I have some issues trying to understand what she is trying to explain.
Without a clear, concise description of the problem it's tough to be specific. It's possible the transmission is starting to fail after nearly 20 years and 290,000 miles. Have you taken it on a test drive to try replicating the problem? Has the transmission been regularly serviced?
Sorry for taking a while to reply, I did take a test drive around my city and out on a expressway, it did not do it when I drove it, and I try to change the transmission fluid every 10 months