Q: Car Sputtering at Hwy Speeds

There are several things that can cause this kind of sputtering to happen, however one that is very common is in fact the camshaft position sensor failing which can cause problems with ignition timing resulting in sputtering as you describe as well as many other problems. As you may know, the camshaft position sensor is a magnetic sensor that monitors camshaft speed to regulate ignition timing and fuel injection timing. It gathers and sends information about the car’s camshaft speed (and as a result the position of each piston) to the car’s electronic control module. This information is received by the computer, which then uses this data to further calculate the time of ignition and the timing of fuel injection required by the engine. When this is not working properly, you may experience a drop in power, poor idling, poor fuel mileage and problems starting the vehicle. As the sensor begins to fail and gets worse over time, the signal it provides to the computer weakens as well. I would recommend having a professional from YourMechanic come to your location to diagnose your camshaft position sensor.