Question

Do all spark plugs need to be replaced at once?

When spark plugs are bad and need replaced do all the spark plugs need replaced at the same time or can you replace them one by one or a few at a time?

Answer 1

Yes when a spark plug fails all the spark plugs in a vehicle should be replaced at the same time.

If you don't replace every spark plug then your engine won't run correctly like it would with all new spark plugs.

When buying spark plugs for your vehicle they usually come in a set and are very cheap to buy and replace them yourself.

I don't think you'll find a shop willing to replace only one or two spark plugs. Replace all spark plugs at the same time to get better gas mileage and better engine performance.