Skip the auto shop - Our mechanics make house calls

Q: Car jerks at a steady speed.

asked by on

Ok so I have been having issues. My car has been jerking slightly while I'm keeping it at a steady speed. Such as 45 mpg. I have replace the throttle position sensor and the speed sensor on the tranny. Still no good. I don't know what else can cause this. Perhaps could it be a clogged fuel filter or injector!

My car has 170000 miles.
My car has an automatic transmission.

A: This may be a sign of a dirty or failing ma...

This may be a sign of a dirty or failing mass air flow sensor. The mass air flow sensor is a unit in the intake system that monitors air intake as it is mixed with fuel prior to being injected into the motor. When this is dirty or faulty, this causes an imbalanced air/fuel load to be supplied to the motor which results in an over fueling or under fueling situation depending on the conditions. This type of inconsistent fuel supply to the motor may cause a hesitation, loss of power, a jerking reaction, potentially a bit of black exhaust smoke and typically a strong smell of fuel when this sensor is malfunctioning. When this is not working properly, you may also notice a strong smell of fuel. I would suggest having a professional from Your Mechanic come to your home to diagnose your mass air flow 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!

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: Check engine light and car idles low/runs differently

This may be related to a dirty or failing idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at...

Q: Low idle, lots of smoke from the exhaust, feels like no power. Mechanic looked at it and said to change my oil grade?

Hi there. From the description you have provided, there is a combination of things happening with your vehicle. If the exhaust smoke is oil smoke, increasing the oil viscosity could help reduce the oil consumption. It could be, the piston...

Q: Trying to swap a 3800 series 2 motor from an 03 impala to an 04 Bonneville will it work

Hi there. You might want to consult with a local engine swap mechanic on this one. Since we don't offer this service to our customers, we try to stay away from giving definitive answers on whether or not engine swaps...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
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.