What Causes an Automatic Transmission Car to Suddenly Stall at a Traffic Light?
2 Answers
The main reason is the use of low-quality fuel, which causes engine carbon buildup and stalling. Here are the specific reasons: Poor Fuel Quality: Automatic transmission models do not easily stall, while manual transmission models may stall frequently due to insufficient driving skills. However, it is not impossible for automatic transmission cars to stall. The main reason is the use of low-quality fuel (many gas stations sell impure fuel for excessive profits), leading to engine carbon buildup and stalling. Driving Skills: Additionally, for new cars (automatic transmission), the main cause of stalling is insufficient driving proficiency. Fuel System Issues: Another possibility is problems with the car's engine or fuel system. However, for new cars, the likelihood of engine-related issues is low, and most cases are due to fuel system problems. For older models, aside from insufficient driving skills, stalling can also be caused by using substandard fuel, leading to engine carbon buildup and other related issues.
My automatic transmission car stalls at traffic lights, which is a fairly common issue, likely related to unstable idling. When the engine is idling, if the throttle body has too much carbon buildup or the mass airflow sensor is dirty, insufficient air intake can cause the RPM to fluctuate, making it prone to stalling. I experienced this before with an older car—it would inexplicably stall at red lights and only restarting helped. Cleaning the throttle body later fixed the issue. To prevent this, avoid frequent short trips, as repeated cold starts can lead to carbon buildup. Additionally, a stuck or aging idle control valve can also cause stalling. If it happens repeatedly, get it checked at a professional shop before it worsens. Restarting and accelerating after stalling could damage the transmission and compromise safety. While not a major issue, addressing it promptly can save a lot of trouble.
