What are the symptoms of a faulty car throttle?
3 Answers
The symptoms of a faulty car throttle are: 1. Unstable engine idle speed, persistently high idle speed that doesn't drop, difficulty in engine starting, especially cold starting; 2. Unstable engine idle speed or no idle speed; 3. Difficulty in engine starting; 4. Insufficient engine power, poor acceleration performance, and unstable operation; 5. Black smoke from the car's exhaust pipe and increased fuel consumption. The throttle is a controllable valve that regulates air intake into the engine, with two types: traditional cable-operated and electronic throttle. After entering the intake pipe, the air mixes with gasoline to form a combustible mixture for combustion work. It connects to the air filter at the top and the engine block at the bottom.
I previously encountered a throttle body malfunction. At that time, the car was extremely difficult to start - I had to turn the key multiple times before the engine would fire up. Driving was even more troublesome - at red lights, the tachometer needle would dance erratically up and down while the car shuddered intermittently. The scariest part was when accelerating: pressing the gas pedal would yield no response, then suddenly after a few seconds the car would lurch forward dangerously, making overtaking particularly hazardous. Fuel consumption also became absurdly high - whereas previously a full tank could cover 500 km, during the malfunction I had to refuel after just 300 km. Later at the repair shop, they discovered the throttle body was stuck due to carbon deposits gluing the valve shut. My advice: get it checked immediately upon noticing these symptoms to avoid being stranded roadside.
After repairing cars for so many years, I've seen way too many vehicles with throttle body issues. The common symptoms are the engine warning light turning yellow, and when you scan it with a diagnostic tool, it's guaranteed to show a throttle position sensor fault code. At idle, the RPM fluctuates up and down, and in severe cases, even the steering wheel shakes. Another classic symptom is sluggish acceleration—owners complain that even when they floor the gas pedal, the speed won't pick up. The most recent car I worked on was even more extreme—after letting off the gas, the RPM stayed stuck at 3000 and wouldn't drop, nearly causing the owner to rear-end another car. This is mostly caused by wear and air leaks in the throttle body. Regular cleaning could prevent many of these issues, but unfortunately, many owners wait until it's completely seized before bringing it in for repairs.
