Why doesn't an automatic transmission car move when idling without giving gas?

[CarolineRose]

The reasons why an automatic transmission car doesn't move when idling without giving gas are: 1. Uneven road surface: There may be a slope in front of the car, obstacles in front of the tires, or potholes that hinder the car's movement. The engine's idle speed is relatively low, and the corresponding power is also weaker, insufficient to push the car forward against the resistance; 2. Rusty brake discs: Brake discs are made of iron and are prone to rust after rain or car washing. At this time, the resistance is greater, and the power during idle speed cannot overcome the resistance. The method of using the automatic transmission electronic parking brake is: 1. Step on the brake, and with the vehicle stationary, pull up the electronic parking brake button to activate it; 2. Step on the brake, and with the vehicle stationary, press down the electronic parking brake button to release it.

[LeCorey]

I've been driving automatic transmission cars for many years and have encountered situations where the car doesn't move when idling without giving it gas. This is usually normal because the idle speed is set too low, and the engine's power output isn't sufficient to drive the wheels to start moving. Especially on flat roads with no load on the car, this is more likely to happen. However, if the car used to move but suddenly doesn't anymore, it could be a sign of a problem. The most common issues are a dirty or clogged idle control valve or throttle body, leading to poor air-fuel mixture and inability to increase RPM. Another possibility is deteriorated transmission fluid, causing the torque converter to slip and fail to transfer power effectively. Another reason could be a faulty throttle position sensor, causing the car to remain unresponsive without input. In such cases, I recommend not forcing it and trying a simple throttle body cleaning first. If that doesn't work, take it to a professional shop as soon as possible to check the idle system and electronic control unit to ensure driving safety. For daily driving, regular oil and transmission fluid changes can help prevent such issues.

[DelMicah]

As a veteran driver with twenty years of experience, I believe the issue of automatic transmission vehicles not moving when idling without throttle input primarily stems from improper idle speed adjustment or aging mechanical components. The idle speed is typically set between 700-800 RPM; below this range, the car tends to remain stationary. If there's unstable oil pressure or a faulty fuel pump, power delivery gets stuck. Worn torque converters or insufficient transmission fluid in the gearbox can also reduce transmission efficiency. More severely, faulty signals from the engine control unit (ECU) may cause excessively low idle speeds. Having driven various models, I've noticed this problem is more common in high-mileage vehicles, especially when transmission fluid changes are neglected. To address it, first check the idle speed gauge reading—if it's low, reset the ECU or update the software. Developing a habit of regular maintenance to keep mechanical components running smoothly is the most reliable approach.

[Emilio]

My automatic transmission car sometimes doesn't move at all at idle, and I need to lightly press the accelerator. This is actually a normal design for most automatic cars, not a major issue. The idle speed is inherently low, so without thrust, the wheels naturally don't move, similar to a safety feature to prevent accidental operation. However, if it used to creep forward slowly but now doesn't, it's worth noting. It could be due to carbon buildup clogging the idle control motor, restricted airflow causing low RPM, or minor issues with the air flow meter detecting inaccurately. Also, check if the throttle pedal sensor wiring is loose. In city traffic jams, suddenly not being able to start is quite troublesome—I've experienced the awkwardness of being honked at by cars behind me at a red light. When this happens, don't panic; try restarting the engine or simply cleaning the components. If that doesn't work, contact a mechanic to check the battery and sensor system.

[NadiaRose]

As an automotive enthusiast, I've studied the mechanisms behind automatic transmissions not moving at idle. The root cause lies in insufficient torque output from the engine during idle to propel the entire vehicle. Common causes include excessive hydraulic resistance in torque converter design (won't rotate without oil pressure), or throttle position sensor data deviation causing the ECU to misinterpret commands and maintain idle below standard values. Another factor could be a stuck idle air control valve (IACV) with insufficient opening due to carbon buildup. During cold starts, thick engine oil affecting fluidity exacerbates this phenomenon. My recommendation is to first use an OBD scanner to check error codes, then perform targeted cleaning of the air system and idle speed adjustment. While DIY solutions can address some issues, seek professional help when needed to avoid transmission damage. Regular use of high-quality oil helps reduce impurity accumulation and maintains proper power transmission.