Does the amount of gas in my gas tank affect the performance and maintenance of a car? Are there are any advantages or disadvantages to either running the gas tank all the way down or topping it up when it gets filled? Is there a 'preffered' amount of gas a car should have (i.e. keeping the tank between a third and two thirds full)?

I've been bit curious about this recently since I've found more gas station that are same price cash or credit and find credit to just be more convenient. One of the side benefits of this is that instead of having to fill up a 'round number' worth of gas (i.e. $20), I usually just fill up the tank completely. I'm curious to know whether that has any performance effects on the car as a whole as opposed to smaller, incomplete fill-ups.

While I'm curios to know of a general answer to this question as well, if this varies based on car, I'll use a 2002 Toyota Avalon for this example.

  • Welcome to Motor Vehicle Maintenance & Repair! I'm pretty sure this Q&A will answer your questions. Be sure to read all of the answers. Jun 22 '18 at 19:32
  • @Pᴀᴜʟsᴛᴇʀ2, man, you're good. I tried searching for a duplicate, but couldn't find one. Thanks! :) Jun 22 '18 at 19:35
  • Having had a (very) quick read of the answers on the duplicate - one point was not addressed and that is some diesels are designed to cause the engine to intentionally misfire when getting too low on fuel so it is effectively saying "You Must Fill Up" and after a short distance it will then turn off the engine until it is refilled (at least 15 litres springs to mind). Before anyone comments this is to save the certain damage to the fuel pump that is in the tank and it is seriously expensive...
    – Solar Mike
    Jun 22 '18 at 19:45
  • A diesel misfiring? A funny combination of words.
    – juhist
    Jun 22 '18 at 20:41

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