A car jerks because of a clogged fuel injector, a dirty fuel filter or because the transmission is about to fail. If the engine is manual rather than automatic, then the car might jerk because of improper shifting.
According to Larry Carley from "Import Car Magazine," one cause of a car's jerking is a clogged fuel injector. A dirty fuel injector doesn't deliver the correct dose of fuel, causing a lean misfire, which feels like the car is jerking. This often occurs when cheaper gas is used because some suppliers use less detergent to keep costs down. The fuel injector can be cleaned using fuel additives.
According to the Ford website, a dirty filter can also cause a car to jerk. The fuel filter optimizes the ratio of fuel and air in the engine. If the car jerks when the RPMs go up, this is a sign that the filter needs changing, typically at a service station.
According to the Samarins website, one of the most significant issues that causes a car to jerk is a faulty transmission. The transmission shifts the car between gears. So, if it is starting to fail, the car shifts hard. The car might just need more transmission fluid or a flush. If the gears inside the transmission break, though, then the transmission either has to be rebuilt or replaced.