Skip the auto shop - Our mechanics make house calls

Q: Car Sputtering at Hwy Speeds

asked by on

My van has a very intermittent sputter at highway speeds. (Feels like it's running out of gas.) It typically happens between 40-70 mph with no engine light. But is not consistent enough to create. If I cruise at say 65 mph it will not happen even when going up and down a hill, however it occurs when I am accelerating up to that speed. It does not make difference of I accelerate fast or gradually. I have changed the spark plugs and wires and have tried a fuel treatment. Other then this issue the vehicle runs excellent and has been perfectly maintained. Internet research has suggested the cam shaft synchronizer assembly. I didn't know if that sounded accurate.

My car has 200000 miles.
My car has an automatic transmission.

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Car Sputtering at Hwy Speeds

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: my car turns over but will not start.

If no power is supplied to the coil packs this would suggest that the ECU is bad as it is responsible for supplying the power to the coil packs. Coils typically have 12V+ supplied to them from grounding from the...

Q: crank but not start

Hello, thank you for writing in. When it comes to vehicles that crank but do not start, there are several tests that can be done. There are a few that need to be done first before you should progress to...

Q: Putting pitman arm onthe power steering gearbox

Hello there, the power steering gearbox and pitman arm are critical steering components on your 2001 GMC Yukon. The pitman arm must be torqued properly so it sits on the splines properly preventing it from loosening over time. A regular...

Related articles

What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.