I have an 09 altima. When I was driving on the interstate, I lost power and it would only get to 60 mph. When I exited to interstate it started acting right. Car sat for about 2 hours when I had to leave again. I drove for about 30 minutes and as I was slowing down to make a turn, it started jerking real bad. Then when I tried to speed up, it jerked even harder. I got it back home, now when I put it in reverse, I have to almost floor it to get it to move and it still Jerks. It smooths out once it gets to about 35 mph. It almost feels like it's stuck in a high gear. Could that be the case?

 

It may be a worn Johnson Bar. The Johnson Bar is not only to allow better vehicle control,but it also sends a mechanical signal to the transmission on optimum gear change. If defective, you may tend to feel as if losing power. Have dealer inspect it as it is a bit tricky to see. It should fix your issue.