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Q: 1. Car jerk 2. Battery

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After driving 30-40mins perfectly my car starts jerk while i guess 2nd gear change and low performance as well on pickup after that i stop my car and off engine and start again its work again smooth for 30-40mins then again its start jerk.

And

While driving car sometimes near meter i see battery icon and engine stop and some time battery icon blinks many times but car working perfectly plz note my battery wires are fine and i placed new battery...

My car has 320000 miles.
My car has an automatic transmission.

The jerking reaction may be related to what is known as the 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 bot 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.

The battery icon suggests you have some kind of failure or problem with your charging system. This consists primarily of your battery, alternator and voltage regulator. the alternator is responsible for charging the battery while the engine runs by generating amperage and recharging the battery while the engine turns the alternator. The voltage regulator is a unit that regulates the charging of the battery by the alternator. When the voltage regulator is not working properly, this may result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. In other cases it may result in the alternator not supplying enough power to the battery, resulting in undercharging the battery or not charging it at all. In some cases when a battery is too weak or damaged, it may no longer hold a charge for any length of time, in which case the alternator may be doing its job, but the battery is just simply too weak to hold a charge. I would suggest having a professional from Your Mechanic come to your location to take a look at your vehicle.

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