I do a lot of coasting in neutral. This has me a bit worried:
"An idling engine isn't operating at its peak temperature, which means that fuel doesn't undergo complete combustion. This leaves fuel residues that can condense on cylinder walls, where they can contaminate oil and damage parts of the engine. For example, fuel residues are often deposited on spark plugs. As you spend more time idling, the average temperature of the spark plug drops. This makes the plug get dirty more quickly, which can increase fuel consumption by 4 to 5 percent. Excessive idling also lets water condense in the vehicle's exhaust. This can lead to corrosion and reduce the life of the exhaust system."
idling-myths
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