To find out what your *specific* Sebring's RPM should be at 70 mph, you'll need to:
* Check your vehicle's specifications: Your owner's manual will likely have a chart or graph showing expected RPM at various speeds for different gears (if manual). If automatic, it may provide a general range.
* Observe it yourself: Drive at a steady 70 mph on a safe, level road and check your tachometer. This provides the most accurate reading for your car.
A significant deviation from what others report for similar Sebrings *could* indicate a problem (like a slipping transmission or incorrect tire size), but it's not necessarily indicative of a fault. The best way to know if your RPM is within the normal range is to consult your owner's manual or observe your own car's behavior.