What Causes the Shaking When Releasing the Throttle on the Highway?
3 Answers
The reasons for shaking when releasing the throttle on the highway are: 1. Insufficiently high RPM during gear shifting, causing the car to shake; 2. Issues with the engine's suspension; 3. Resonance occurring when the engine RPM and vehicle speed are at the same frequency. The functions of the throttle are: 1. Controlling the engine's RPM by adjusting the pedal pressure; 2. The throttle regulates the carburetor, determining the engine's output power. The working principle of the throttle is: Pressing the throttle pedal directly controls the throttle valve. The throttle valve opening increases, allowing more air to enter the engine. At this point, the ECU commands the fuel injection system to inject more fuel, increasing the engine's RPM and thus accelerating the vehicle.
I also experienced car shaking when releasing the throttle on the highway before. The mechanic later explained several possible causes to me. The most common one is severe engine carbon buildup, especially around the throttle body and fuel injectors. When you release the throttle, the sudden reduction in air intake makes the engine 'gasp for breath' and start shaking. Aged spark plugs are another hidden danger - unstable ignition makes shaking more likely when lifting off the throttle. Additionally, rubber components like engine mounts harden with age, transmitting vibrations that should have been absorbed directly to the car body. My suggestion is to get it checked immediately if you notice this condition. Don't underestimate the shaking - in serious cases it might affect steering control.
As a long-distance driver, I've found that shaking when releasing the throttle on highways is mostly related to the drivetrain. Rear-wheel drive vehicles require special attention to driveshaft balance issues – even slight misalignment or worn universal joints can cause immediate shaking when torque changes abruptly upon throttle release. For front-wheel drive cars, worn CV joints can also cause similar symptoms. Poor tire balance can also lead to shaking within specific speed ranges, especially after tire replacement without proper balancing. I once experienced severe steering wheel vibration when releasing the throttle at 80 km/h, which turned out to be incorrect toe angle alignment. These mechanical issues are best diagnosed at professional repair shops as they're difficult to fix yourself.
