I have previously used the Hyundai Fuel System Cleaner (treats 20 gallons), but it is just too expensive. Since I am using MaxLife now I decided to purchase Valvoline's fuel system cleaner. It is 1/3 the price and treats 15 gallons which is perfect because the Elantra has a 14 gallon fuel tank. I hope all goes well since Hyundai says you "have" to use their product, but I am out of warranty anyway.
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