Use Top Tier gas if you have a direct injection engine. Period.
A bunch of manufacturers got together and developed a performance standard for gasoline called Top Tier. Dozens of retailers, from Amoco to Valero, get their gasoline additive packages inspected for their ability to keep your engine clean and free of metal contaminants. A recent scientific experiment conducted by the American Automobile Association, yielded some pretty clear-cut results. When comparing Top Tier with non-top tier gasses in a controlled environment, "non-TOP TIER gasolines caused 19 times more engine deposits than TOP TIER brands after just 4,000 miles" (emphasis added).
Remember, it's about brands -- not octane levels -- so unless your car specifically calls for premium, you can get the lowest grade so long as it's from an approved brand. The cost difference between Top Tier gas and the cheaper stuff averages out to only three cents, but the impact on a direct-injection engine is simply enormous. This is a no-brainer, people. You can find the list of gas retailers here. There are over 40 to choose from.
Won't the expensive gas cost more than repairs?
Nope. Not even remotely close. Assuming you drive your car for 100,000 miles and average 25mpg, you’re only really saving $120... before taking in the real expenses to your bottom line. Because the cheap gas can gradually destroy far more expensive parts of your engine, be prepared to replace things like injectors, which can cost anywhere between $500 to over $1,000 to have replaced.
Some have tried everything from chemical cleaners to blasting the valves with walnut shells (really!). These treatments cost around $400 to $600 and often times they’re too little, too late, and well after the warranty period.
If you use Top Tier gas and follow the maintenance schedule, a direct injection engine can potentially save you well over $1,000 in fuel savings and greatly improve every aspect of your driving experience compared to a non-DI engine. So do yourself and anyone that owns your car after you a favor: invest in your vehicle and keep those walnut shells in the trash where they belong.
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