Prius went from 45 mpg to 22-30 mpg after sitting for three weeks?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Falcon143, Aug 28, 2024.

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  1. Falcon143

    Falcon143 New Member

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    Hi hybrid battery is refurbished but on the newer side. Gas mileage was great at 45 mpg, I left town for three weeks and now it’s getting 22-32 mpg. Tires are good, brand new 12 volt battery. I’ve never had a hybrid battery go out so drastically. Any other causes? Spark plugs were replaced a few years ago and I only drive it locally and not often since then. I’m hoping it is not the hybrid. Odd that after sitting it shifted so quickly. Brakes got changed during this time, there’s still some squeaky noise when not breaking sometimes.
     
    #1 Falcon143, Aug 28, 2024
  2. Tombukt2

    Tombukt2 Senior Member

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    Maybe the brakes are dragging or something the rears are drums some people don't work on those so well I don't know but yeah that's a you know half of your mileage drop I mean generally this happens if I pull the trailer yeah even just locally things like that but I mean a couple year old spark plugs really shouldn't make a lot of difference unless they are at the end of their lives regardless generally what goes in these are 100,000 mile SK16s
     
    #2 Tombukt2, Aug 28, 2024
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  3. JC91006

    JC91006 Senior Member

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    The problem is 99% the rebuilt battery that sat for 3 weeks.
     
    #3 JC91006, Aug 28, 2024
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  4. PriusCamper

    PriusCamper Senior Member

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    Low tire pressure can cause this. Boost your tire pressure up near 40psi... Also fully charge up your new 12volt with a legitimate charger in the 10amp range because Prius are lousy at quickly recharging 12volt if its been sitting and draining for a while... Also maybe you bought some bad gas, so drive it more often to get a fresh tank of gas in there asap.

    How stable is the charge on HV battery? Does charge level move often? Do they stay stable / just under green bars most of the time?

    Lastly, how many miles on it? Have you had regular maintenance?
     
    #4 PriusCamper, Aug 28, 2024
  5. MAX2

    MAX2 Active Member

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    Need to figure it out.
    Is your high-voltage battery dead?
    Or is your mileage reduced after replacing the high-voltage battery?
     
    #5 MAX2, Aug 28, 2024
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