Why is the idle speed high in the eighth-generation Accord?
3 Answers
If the car has just been started, a high idle speed is a normal phenomenon; if the idle speed remains high after starting, it may be due to a throttle valve malfunction. Below is relevant information about the eighth-generation Accord: 1. Exterior: The increase in size and space is a significant highlight of the eighth-generation Accord. Its length, width, and height reach 4945mm, 1845mm, and 1480mm respectively, with a wheelbase of 2800mm. The spacious dimensions can meet customers' requirements for comfort in terms of space. 2. Powertrain: The eighth-generation Accord is equipped with a newly upgraded Honda i-VTEC engine across the lineup. The newly upgraded 2.0-liter i-VTEC engine features enlarged intake valves, delivering a maximum power of 156 horsepower (115 kW) and a peak torque of 189 N·m at 4300 rpm. The Accord's 2.4-liter i-VTEC inline-four-cylinder engine has smaller spark plugs, redesigned coolant flow, and optimized ignition timing, achieving a maximum power of 180 horsepower (132 kW) and a torque of 225 N·m.
I've been driving an eighth-generation Accord for several years and have encountered high idle speed issues multiple times, usually caused by carbon buildup in the intake system or a dirty throttle body. I remember last summer when my car's idle suddenly surged above 1000 RPM - initially thought it was due to AC usage, but the problem persisted even after turning it off. Later, a professional cleaning of the throttle body and fuel injectors at a specialized repair shop solved the issue. Prolonged engine carbon deposits can affect sensor readings - the mass airflow sensor becomes prone to errors, and the idle air control valve loses responsiveness. For older cars like the eighth-gen Accord, aging spark plugs or faulty ignition coils can also cause unstable idling. Additionally, intake manifold leaks due to deteriorated rubber hoses may trigger the ECU to compensate with extra fuel injection, raising the RPM. When facing high idle, first check if the air filter is clogged. If you're not confident in DIY repairs, seek professional diagnosis - don't underestimate this issue as prolonged neglect increases fuel consumption and damages the engine. Regular engine cleaning to prevent carbon buildup is particularly important for aging vehicles.
My Accord is also an eighth-generation model, and the high idle speed gave me a headache for a while, especially noticeable during city traffic jams. I think the common causes are sensor failures, such as a faulty idle control valve or throttle position sensor, which send incorrect signals to the computer, causing the RPM to rise automatically. Another possibility is clogged or dirty fuel injectors, as poor fuel flow can disrupt the air-fuel mixture ratio. Try listening to the engine sound when starting the car cold—if there's significant shaking along with unstable idle, it's likely the intake system needs cleaning. The eighth-gen Accord's ECU sometimes misadjusts parameters, especially when the battery voltage is unstable. I remember last year my car's idle speed went up right after a battery replacement. It's advisable to pay attention to regular maintenance, like oil and air filter changes, to avoid sludge buildup. If you encounter high idle speed, it's best to take it to a repair shop and use a diagnostic tool to check for trouble codes—safety first, don't risk long-distance driving. Cleaning the throttle body only costs a few hundred bucks, and timely action can save fuel and hassle.
