Q: My car keeps randomly jerking, while the RPM jumps up to 5000+ & then goes back down, while I'm driving at a steady speed.

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This has been happening occasionally for months. I know it's not that it needs transmission fluid, as I had that replaced a few months ago & checked about a week ago.

My car has 121000 miles.
My car has an automatic transmission.

Hello and thanks for writing in. What you are describing sounds like a dirty or faulty 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. This sensor relays vital information to the ECM which uses this to make adjustments to fuel supply to the motor. A dirty or faulty sensor can cause 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. I would suggest having a professional from Your Mechanic come to your home to diagnose and inspect your vehicle.

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