# regular gas vs high test

**URL:** <https://boards.straightdope.com/t/regular-gas-vs-high-test/328536>\
**Category:** Cecil's Columns/Staff Reports\
**Created:** [October 30, 2005, 1:42am UTC](https://boards.straightdope.com/t/regular-gas-vs-high-test/328536 "2005-10-30T01:42:12Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![david\_getlin](https://avatars.discourse-cdn.com/v4/letter/d/8edcca/32.png) [@david\_getlin](https://boards.straightdope.com/u/david_getlin)\
**Post date:** [October 30, 2005, 1:42am UTC](https://boards.straightdope.com/t/regular-gas-vs-high-test/328536/1 "2005-10-30T01:42:12Z")

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hello, cecil…i read your colum on regular vs high test gas…and was ready to take your advice and follow the manual…but…the last sentence changed my mind…you alluded to using a 6 dollar bottle of carbon cleaner rather than spending an extra 150 bucks on high test gas per year…

i inherited a lexus 1997 series 400 8 cylinder car…first couple tanks of gas i used was regular and i noticed nothing different in driving…of course, gas being expensive and me being retired, i tho’t i would save some money…

are you saying to use carbon cleaner, perhaps once a month, and putting regular gas in the tank…thanks, so much…dg

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**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\
**Post date:** [October 30, 2005, 2:25am UTC](https://boards.straightdope.com/t/regular-gas-vs-high-test/328536/2 "2005-10-30T02:25:12Z")

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Got a link to the column?

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**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\
**Post date:** [October 30, 2005, 5:56am UTC](https://boards.straightdope.com/t/regular-gas-vs-high-test/328536/3 "2005-10-30T05:56:53Z")

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Welcome to the SDMB, david getlin.

It’s appreciated if you can provide a link to the Straight Dope column you’re commenting on, if the column is online. That keeps everybody on the same page. Providing a link can be as simple as pasting the URL into your post, making sure to leave a blank space on either side of it. Like so: [http://www.straightdope.com/columns/041008.html](http://www.straightdope.com/columns/041008.html)

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**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\
**Post date:** [October 30, 2005, 1:52pm UTC](https://boards.straightdope.com/t/regular-gas-vs-high-test/328536/4 "2005-10-30T13:52:37Z")

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You’re misinterpreting what Cecil said. He’s saying _if_ you have an old beater that runs on regular, _and_ you’re concerned about knock sensors masking the effect of carbon buildup, _then_ use a bottle of carbon cleaner instead of switching to premium. He’s _not_ saying to use carbon cleaner with regular gasoline in cars designed to run on premium.

In fact, what he’s saying in the article would explain your experience with your Lexus: due to the knock sensors, the engine timing is changed, so you can use regular gas in a car intended for premium without hearing it ping. However, that will also result in poorer performance and an increased use of fuel. So you might very well be spending _more_ money on regular, because your mpg will decrease.