Is it harmful for my son to use Premium gasoline in his 1997 GMC Sierra pickup?

Answer 1

No it has a higher octane rating that helps prevent detonation ( knocking)

AnswerIt is a myth that cars run better on premium gas, and this myth costs you money big time. Buying premium gas for a truck that only requires regular and you are wasting your money. Mechanics, and car makers will tell you that for 90 percent of the cars sold today, high octane is no better than regular gas. It won't give you better mileage, more power or a cleaner engine. Some cars do need higher octane � older cars that knock, and cars with high-compression, high-revving engines like Ferraris, Bentleys, Jaguars, Acuras, Mercedes and Corvettes. But 90 percent of new cars don't need it � check your owner's manual. The car manufacturers and every car expert will tell you that for most cars, high octane is a waste of money. Even the gas companies that sell the high-octane fuel � and make more money off of it � admit most people don't need it. But they don't go out of their way to tell you that. The compression ratio of your engine determines the octane rating of the gas you must use in the car. Octane has nothing to do with power or mileage. Can using a higher octane than necessary be harmful? The use of the higher octane will not normally harm the engine. But with some low compression engines, the use of high-octane gas in cold weather can cause hard starting, stalling and hesitation when cold. On some older vehicles, the high octane could even cause the computer to set off a knock sensor fault code because the computer could not advance the timing far enough to actually test the knock sensor. Bottom line: Use the correct Octane fuel that is required for you car or truck. If it says use Regular then use Regular. The only instance when the use of Premium in an engine designed for Regular is appropriate is an engine that is pinging and nothing else works to prevent the pinging. In that case the use of premium is appropriate as pinging can cause serious damage. Answer

Actually, it can harm your vehicle. I had a 99 Miata and used only premium gas it thinking I was getting better gas mileage and that it was cleaner burning. NOPE. I had to replace my catalytic converter after many years of use because it was clogged with soot and restricting the exhaust. Afterward, I experimented with regular, it knocked and then mid-grade. My fuel economy actually went up and it burned cleaner. If your car doesn't require premium, don't use it.

Just my experience, yours may vary.