How to Restore High Fuel Consumption After Replacing Spark Plugs?
2 Answers
It is normal for fuel consumption to increase immediately after replacing spark plugs, and no adjustment is needed as it will naturally recover. One possible reason is that the mechanic did not tighten the spark plugs according to the manufacturer's specifications during replacement, leading to air leakage. Loose spark plugs causing air leakage can result in reduced engine power, easier stalling at high speeds, and consequently increased fuel consumption. Here are other possible reasons for increased fuel consumption: 1. Overfilling engine oil during maintenance: If there is too much engine oil, the crankshaft becomes submerged in the oil, increasing resistance and naturally raising the engine's load. To achieve greater power, fuel consumption inevitably increases. In some cases, fuel consumption can even double, though this has nothing to do with the spark plugs. 2. Incorrect spark plug model: Automotive components have very strict dimensional requirements, and even a slight deviation can affect vehicle safety and normal operation. For example, if the spark plug gap is 0.6mm but a 0.9mm gap spark plug is installed, the excessive gap will affect the entire ignition system, reducing the success rate of ignition.
Having worked in car repairs for many years, I often encounter cases where fuel consumption increases significantly after replacing spark plugs. Common causes include improper installation or mismatched spark plug models. You should check the spark plug gap—if it's too tight or too loose, it can lead to incorrect ignition and incomplete combustion, resulting in higher fuel consumption. Use a gap gauge to adjust it properly; the ideal gap is typically around 0.8-1.0 mm. The spark plug model must match your vehicle—using low-quality or mismatched plugs can increase fuel consumption, so check the manual to confirm the correct model. Also, ensure the spark plugs are tightened sufficiently, as loose connections can cause poor contact and affect performance. While you're at it, clean the air filter, as a clogged filter reduces airflow and raises fuel consumption. After replacement, drive gently for a few days to let the car adapt, avoiding aggressive acceleration for smoother and more fuel-efficient driving. If the issue persists, test the ignition coil voltage or visit a professional repair shop for diagnosis. Don’t overlook this seemingly minor issue—address it early to ensure safe driving.
