I was going to Wal-Mart today and decided to use Sport (S) mode plus shifter. Something strange happened. Gear 1 to 4 was fine, but 5 and 6 were strange. By strange I mean the car stucked at 2000 RPM and speed at 60 MPH. I floored the accelerator, nothing changed. When I returned, I used D mode and everything was normal. Is the car telling me something bad is lurking?