Has this happened again? Also, how do you know that it lost 20 litres of fuel? That is a lot of fuel or did you lose 20L of gas mileage? Meaning you were getting 30L per mile and then you started getting 10?
I would not be so concerned with the lose of fuel mileage if that is what is was because that is just a calculation and it will be corrected as soon as it doesn't see this issue happen again.
However, the lack of acceleration sounds like a fuel issue so I would suggest starting with checking for codes.
https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing
Then we need to remove the spark plugs and take a look at them to see if they can give any signs of what may be happening.
Below is a chart of what plugs look like based on different issues. However, if this only happened once and has not happened since, it is going to be difficult to determine what happened.
Let's run through this info and let us know if you have any codes and we can go from there. Thanks
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Sunday, May 30th, 2021 AT 5:31 PM