Why does the new spark plug cause idle vibration?
3 Answers
Idle vibration after replacing a new spark plug may be caused by damaged or broken cylinder wires during the replacement process, leading to abnormal ignition. Alternatively, it could be due to installing spark plugs of a different model. If the issue is confirmed to be related to the spark plug, simply replacing it with the correct model can resolve the problem. Below are some relevant details: 1. A car operates by relying on the engine, and the smooth running of the engine depends on the continuous sparking of the spark plugs. Spark plugs are wear-and-tear components that naturally degrade over time, requiring replacement. 2. As a consumable part, spark plugs experience gradual wear on their positive and negative electrodes with prolonged use, leading to an increased ignition gap. However, this change is gradual and affects other related parameters as they adjust accordingly. Therefore, when a vehicle's spark plugs are significantly worn, the ignition gap also increases. For example, if the original gap was 0.8 and it increases to 1.1 before replacement, the excessive difference and rapid change can cause engine damage if not properly recalibrated.
I just replaced my spark plugs last month, but the car shakes violently at idle, like it's dancing. Later inspection revealed that the main issue was careless installation - the torque was either too tight or too loose, causing poor compression of the spark plug sealing ring and gas leakage. Unstable combustion chamber pressure then led to shaking. Alternatively, if the spark plug model doesn't match the vehicle (with a heat range that's too high), it can cause ignition delay and disrupt idle control. I suggest also checking if the high-tension wires are aged, as poorly matched ignition coils can amplify the problem. Even new spark plugs can cause shaking if they're cheap knock-offs with improperly adjusted electrode gaps or substandard quality. Don't forget to clean the idle control valve - excessive carbon buildup can make the shaking more noticeable. For safety, take it back to the shop for a comprehensive technician inspection rather than tinkering yourself.
Experiencing rough idle after changing spark plugs is something I've been through. The issue might stem from system compatibility, such as altered ignition characteristics of the new spark plugs causing the ignition coils to lag or exposing unstable high-voltage wire connections. Air-fuel ratio imbalance is common—check for excessive throttle body carbon buildup or a clogged air filter, and use a diagnostic tool to read trouble codes for efficiency. Choosing counterfeit spark plugs with poor electrode craftsmanship leads to higher ignition failure rates, naturally causing vibrations. Opting for genuine OEM parts is safer; don't penny-pinch only to invite bigger problems. Also, investigate fluctuating fuel pump pressure—a comprehensive repair approach proves more effective than solely focusing on spark plugs.
