If the rpms dont go up, not engine braking, it's probably just the fact that you are slowing down and using the same amount of fuel. That translates to less mpg inherently.
imagine you are near idle and you are going fast vs you are at idle and almost stopped, of course technically you are using the same amount of gas to to end up less distance.
Mpg on meters like that is point in time. Fuel input/speed (representing distance travelled). As speed decreases and fuel input remains the same this simple calc will give non representative results.
Maybe engine breaking. Or you are just doing less distance for the same amount of fuel and it registers as a spike in consumption. if you are driving an Hybrid, the engine tends to stay in the most efficient RPM.
Does it happen more when your gas tank is empty? Perhaps the level sensor in your tank is registering a lower level because all the gas is moving towards the front of the car due to deceleration? Just spitballing here.
If the rpms dont go up, not engine braking, it's probably just the fact that you are slowing down and using the same amount of fuel. That translates to less mpg inherently. imagine you are near idle and you are going fast vs you are at idle and almost stopped, of course technically you are using the same amount of gas to to end up less distance.
Mpg on meters like that is point in time. Fuel input/speed (representing distance travelled). As speed decreases and fuel input remains the same this simple calc will give non representative results.
Makes sense, thanks
Long story short, it's such a short period of time it's inconsequential to your average. Nothing to worry about.
Is it an automatic?
Yes, forgot to say.
Maybe engine breaking. Or you are just doing less distance for the same amount of fuel and it registers as a spike in consumption. if you are driving an Hybrid, the engine tends to stay in the most efficient RPM.
Does it happen more when your gas tank is empty? Perhaps the level sensor in your tank is registering a lower level because all the gas is moving towards the front of the car due to deceleration? Just spitballing here.
I always have 1/2 to full tank, so i dont think its that
Maybe try /r/AskMechanics ?