Why does the car idle shake after running on the highway?
2 Answers
The reasons for the car idling shake after running on the highway are: 1. Uneven brake disc surface with large radial runout; 2. Rim deformation; 3. Too high or too low tire pressure; 4. Large deviation in wheel alignment data; 5. Abnormal tire wear; 6. Tire dynamic balance failure; 7. Shock absorber failure; 8. Engine power failure. The solutions for the car idling shake after running on the highway are: 1. Check and adjust the front wheel alignment angles and toe-in; 2. Perform wheel dynamic balance check; 3. Adjust tire pressure or replace tires; 4. Perform drive shaft dynamic balance check; 5. Choose high-quality engine oil; 6. Check the engine ignition system.
After driving for so many years, I often encounter the situation where the engine idles roughly after coming off the highway. The most likely reason is that carbon deposits in the engine have been washed down, clogging the fuel injectors. High-speed driving causes the engine to run at high temperatures, which washes away carbon deposits on the valves and piston tops, resulting in debris clogging the fuel injector holes and causing uneven air-fuel mixture. Additionally, if the throttle body is dirty, it can also cause this issue, especially since electronic throttle bodies are particularly sensitive to carbon buildup. Last time I experienced severe shaking, I solved it by disassembling and cleaning the throttle body and intake manifold. It's recommended to first read the fault codes to rule out issues with the ignition coils. If there are no obvious faults, the simplest solution is to directly clean the fuel system.
