I recently bought this car and I've noticed that it jumps or jerks forward when I almost come to a complete stop. It's like right before I fully stop that it does it. When I accelerate it changes gears it's kind of sluggish but it's not too bad. I have a "live" MPG cage on my car and right before the jerk it goes all the way down like I'm pushing the gas but I'm not and my RPM doesn't change. My RPM only moves a little when I'm waiting at a stop and it vibrates the car sometimes. I mainly want the jerk fixed. I don't think it's the brake rotors or pads because they look fairly new. Could it be the transmission fluid? Does it need to be changed? Does it need to be flushed? I can't check it on my car because it's under the car.
My car has 120000 miles.
My car has an automatic transmission.
Hello, What you are describing may be a result of a faulty speed sensor, potentially low transmission fluid or a even a faulty transmission control solenoid. As your vehicle travels down the road, the computer analyzes data being sent by vehicle speed sensors and engine speed sensors. Based on this information, the Engine Control Unit (ECU), or the Transmission Control Unit (TCM), executes the appropriate upshifts and downshifts by sending a signal to one of several shift solenoids. These transmission solenoids have spring-loaded plungers inside them, which are wrapped with wire. When this coil of wire receives an electrical charge from the TCM / ECU, it causes these plungers to open, allowing transmission fluid to flow into the valve body and pressurize the desired clutches and bands. When this happens, the transmission changes gears and you continue down the road. The computer controls the transmission solenoid in several ways. If the vehicle is equipped with a dedicated Transmission Control Unit, it can open or close the hydraulic circuit using a direct 12v signal. In some cases, the Engine Control Unit (ECU) can control the solenoid’s plunger by turning the ground circuit on and off. When this is not working properly, this can cause a jerking reaction, a delay in shifting or in some cases may cause the transmission to hesitate in shifting gears. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your transmission.
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