I have a 2008 Hyundai Sonata 2.4L 4-speed automatic with 175k miles that's been taken care of it's whole life. Just yesterday as I was accelerating it got to about 23-2500 RPMs and it slightly jerked as the rpms fell and then would accelerate no further until I put it in manual and put it into 2nd gear. It has the same issue through all of the gears, but it doesn't happen every time I drive it. It seems to be on an every other schedule. I've read about limp mode but this hasn't thrown any errors, though there has been an occasional beep, but I think that's my bluetooth transmitter through the radio not the car. I took it into the dealer and it didn't have the problem so they couldn't diagnose it. The other issue started 2 days ago when each time I start it it takes a little longer every time. They recommended I change the battery but I wonder if anyone has had this issue and they could be related.