What Causes an Automatic Transmission Car to Suddenly Slow Down During Normal Driving?

[MacHayden]

Here are the reasons why an automatic transmission car may suddenly slow down during normal driving: 1. Engine issues: If the problem lies with the engine, it could be due to a fuel pump malfunction, where abnormal fuel pumping causes a more significant drop in throttle response. 2. Transmission issues: If the issue is with the transmission, a mechanic must conduct a thorough inspection. First, a computer diagnosis should be performed to examine the engine data when the problem occurs, making it easier to identify the root cause. Transmission jerking or hesitation often does not result from internal valve body damage but rather from stubborn dirt and impurities inside the transmission. Particularly, when dirt and impurities accumulate inside the valve body, they can form blockages, preventing effective regulation of oil pressure and leading to jerking, hesitation, or slipping issues.