Why does the car jerk and fail to accelerate when running?
3 Answers
Here are the reasons why a car jerks and fails to accelerate when running: 1. Fuel quality issues: The fuel quality is substandard or impure, resulting in low combustion value. Use up the fuel in the tank, drive the car to a maintenance facility, replace the fuel filter, clean the fuel lines, and then refill with high-quality fuel. 2. Intake or exhaust system problems: Blockages in the intake or exhaust system. The intake valve supplies air to the engine for combustion, while the exhaust valve expels the waste gases produced by combustion. When the intake valve opens, the air-fuel mixture is still burning, causing the burning mixture to backfire through the open intake valve into the intake pipe, resulting in a backfire phenomenon.
Once when driving an old car, I felt it jerking during acceleration, like it was gasping for breath, and there was no power when I stepped on the gas. I figured it might be an issue with the fuel system—perhaps the fuel pump was failing, causing unstable fuel supply, or the filter was clogged, restricting fuel flow and preventing gasoline from reaching the engine, which could easily cause jerking. If it's more noticeable during cold starts in winter, it might be an ignition system problem, like worn-out spark plugs causing misfires, making the engine run unevenly. It could also be a dirty air filter, leading to insufficient air intake and an imbalanced air-fuel mixture, making the car act erratically. I recommend getting it checked as soon as possible—don’t delay, as breaking down on the road would be a hassle.
I think this situation is quite common, don't worry too much. Engine hesitation during acceleration is mostly caused by fuel system or ignition issues. For example, if the spark plugs are worn out and the gap is too large, causing weak sparks, it will result in jerking; if one cylinder's ignition coil fails, the power output becomes uneven. Regarding fuel system, unstable fuel supply pressure from a faulty high-pressure fuel pump or clogged fuel injectors causing poor spray can both lead to power interruption. Also, don't overlook the transmission - for manual transmissions it might be clutch wear causing slippage, while for automatic transmissions it could be faulty shift solenoids. It's best to do some simple self-checks first, see if the air filter is clean or if there are any fuel line leaks. If that doesn't help, take it to a professional shop for diagnosis with specialized equipment.
