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Honda Jazz Forums => Honda Jazz Mk4 2020 - => Topic started by: Braveheart on February 20, 2025, 10:18:34 AM

Title: MPG anomaly
Post by: Braveheart on February 20, 2025, 10:18:34 AM
My Honda Jazz petrol hybrid is 2 years old and has just had it's 2nd service, The mpg seen in the display has recently dropped suddenly from 62 mpg to 42 mpg. Could this be true?  I am a cautious driver and drive always in Economy mode. I do about 2,500 miles per year.
What can be the cause of this? The drive feels just the same and I haven't changed my style of driving.
Any help would be appreciated.
Title: Re: MPG anomaly
Post by: Lord Voltermore on February 20, 2025, 10:29:51 AM
Have you seen the  recent posts from Enfrance ,  on the 'MPG for those interested' thread.  Your anomaly may be for the same reasons  .

https://clubjazz.org/forum/index.php?topic=12364.705

 
Title: Re: MPG anomaly
Post by: Kremmen on February 20, 2025, 11:48:22 AM
Eco mode, in my experience, isn't, because you need more throttle as it dulls it. I can get better MPG with Eco off and a light and gentle foot

As far as MPG is concerned you need to analyse your journeys. If you pull off with a cold engine and drive a few miles then your MPG could easily be in the 30's
Title: Re: MPG anomaly
Post by: Jazzfan49 on February 20, 2025, 11:54:04 AM
Eco mode, in my experience, isn't, because you need more throttle as it dulls it. I can get better MPG with Eco off and a light and gentle foot

As far as MPG is concerned you need to analyse your journeys. If you pull off with a cold engine and drive a few miles then your MPG could easily be in the 30's

What he said, Kremmen nailed it - I’ve used eco for 2years but have it turned off for the last few weeks, resulting in slightly better fuel economy plus it’s so much more responsive and nicer to drive.  ;D ;D
Title: Re: MPG anomaly
Post by: Nicksey on February 20, 2025, 12:12:04 PM
How long is your average journey?

2500 a year is incredibly low, so is it possible your journeys are very short too.

The average MPG is always based on that singular word.. 'average'.

If you are not getting up to decent mileage and speed, then it will always be based on the most recent trips.

My Jazz is just over 2 years old, has done 27k and the shortest journey is around a 6 mile round trip, the longest (recently) a 70 mile round trip. I have been seeing 66mpg over winter, 74mpg last summer...
but. it will take a few miles of driving (even in town) for the mpg to climb to around the 55mpg mark. In some instances early on I only see 30mpg.. but thats because the average hasn't had time to settle.
Title: Re: MPG anomaly
Post by: John Ratsey on February 20, 2025, 12:28:18 PM
My Honda Jazz petrol hybrid is 2 years old and has just had it's 2nd service, The mpg seen in the display has recently dropped suddenly from 62 mpg to 42 mpg.
The displayed mpg is based on the recent usage history. How many miles have you done since the service? The service process will hit the mpg because the vehicle has probably been moved short distances several times and the engine may have also been running on idle in the workshop (the recent cold weather won't have helped). Go on a reasonable trip and the mpg should rise. If not, there's cause for concern.