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Q: Jerking reaction when accelerating

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It started as with left turns. Any time I would make it, it would make a squeaking sounds then almost pause before it would accelerated causing a small jerk, now it does it just driving straight.

My car has 118000 miles.
My car has an automatic transmission.

A: This may be a couple of different things. W...

This may be a couple of different things. When a transmission is low on fluid, this can cause a jerking reaction as you describe. Automatic transmissions use pressurized hydraulic fluid to change gears. Every time a gear change is required, the car’s computer activates a transmission solenoid, which directs transmission fluid into the valve body to engage the correct gear. When the transmission is low on fluid, this can cause a jerking reaction as you describe.

This may also be related to something called a mass air flow sensor. The mass air flow sensor 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 recommend having an expert from YourMechanic come to your location to take the car for a test drive to more specifically determine the cause for this type of jerking reaction.

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