Mpg goes down while idle

[Maglin]

I want to know my mpg while actually driving. Especially in the winter, I often have the car ruining while stopped.

That is exactly what the MPG is giving you. If your vehicle was idling say 2 hours for every tank of fuel and it only calculated fuel used during actual tire rotation you would end up with numbers that are just complete lies. like 22+ MPG for city driving. I hadn't reset mine for about 5K miles. I did it just a few weeks ago and now I regret it. Going to take forever for it to stop moving around. I think a valid reason to reset is to see the difference between winter and summer driving.

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[Mr. Met]

That is exactly what the MPG is giving you. If your vehicle was idling say 2 hours for every tank of fuel and it only calculated fuel used during actual tire rotation you would end up with numbers that are just complete lies. like 22+ MPG for city driving. I hadn't reset mine for about 5K miles. I did it just a few weeks ago and now I regret it. Going to take forever for it to stop moving around. I think a valid reason to reset is to see the difference between winter and summer driving.

I am not talking about tire rotation, or lack of, I am talking about being in park. Calculating Miles Per Gallon while the engine is on simply because its winter gives you mpg numbers that are just complete lies. I want to know what my mpg is while driving, be it in stop and go city or on the highway. When you are in park you are not driving and are obviously getting 0 mpg. That skews your true mpg. If you let your car idle in park for a full tank of gas your mpg would be 0, does that mean if you put it in drive the car would instantly run out of gas?

 

[wproctor411]

This why newer trucks and SUVs have the bullsh!t start stop feature but it helped manufacturers meet EPA requirements with a simple relay.

 

[GT 550]

does mpg go negative if you drive in reverse?

Yes, and the gas tank refills.

OP check it's still showing mpg at idle, some cars change to gal/hr because idle=no miles

 

[AnthonyA1234]

I am not talking about tire rotation, or lack of, I am talking about being in park. Calculating Miles Per Gallon while the engine is on simply because its winter gives you mpg numbers that are just complete lies. I want to know what my mpg is while driving, be it in stop and go city or on the highway. When you are in park you are not driving and are obviously getting 0 mpg. That skews your true mpg. If you let your car idle in park for a full tank of gas your mpg would be 0, does that mean if you put it in drive the car would instantly run out of gas?

Exactly

 

[CorvZ061]

I am not talking about tire rotation, or lack of, I am talking about being in park. Calculating Miles Per Gallon while the engine is on simply because its winter gives you mpg numbers that are just complete lies. I want to know what my mpg is while driving, be it in stop and go city or on the highway. When you are in park you are not driving and are obviously getting 0 mpg. That skews your true mpg. If you let your car idle in park for a full tank of gas your mpg would be 0, does that mean if you put it in drive the car would instantly run out of gas?

If you let your car idle in park for a full tank it will run out of gas in park, just as it will while driving.

You do understand that while even in park and running the engine is using gas to idle, right? So why wouldn’t it calculate your mpg at all times the car is consuming fuel?

 

[Stang55]

I don't trust the computer. A much accurate way of calculating it is to reset your trip after filling up, then on your next fill up you have the 3 most important values. How far you drove, how many gallons was put in, and the price paid for it. And also you can remember when was your last fill up how many days ago, where did you go, what did you do, etc. I use this method and calculate more than just one thing from the equation

 

[Cobra Jet]

 

[Lime1GT]

This why newer trucks and SUVs have the bullsh!t start stop feature but it helped manufacturers meet EPA requirements with a simple relay.

Why would you say it's a bs feature. It'll save you the consumer at the pumps. As long as it's able to be over ridden by the vehicle owner I don't see a problem.

 

[EFI]

Why would you say it's a bs feature. It'll save you the consumer at the pumps. As long as it's able to be over ridden by the vehicle owner I don't see a problem.

Because it's hard on the engine and it's rough/annoying to drive.

If/when they make it very smooth and indiscernible, then yeah I would agree it would be a nice feature. But the increased wear on many of the parts and poor driveability makes it a BS feature in my book also.

 

[Fly2High]

I find I can improve the number just by getting off the gas, shifting into neutral and coasting slowly up to the light. As long as you move, keep the rpms low, and reduce the time sitting still, the better your mileage is calculated. Benefits of a manual.

 

[gadgtfreek]

#threadmakesnosense

If you idle an entire tank, you get 0 mpg because you didnt move.

 

[Mustangpursuit]

I guess most people disagree but I always thought it was stupid the car keeps calculating mpg while stopped, at least in park. I would hope people understand you are getting 0 mpg while in park with the engine on. I want to know my mpg while actually driving. Especially in the winter, I often have the car ruining while stopped.

My VW Beetle Turbo does that, if stopped the current MPG display Ø and trip avg MPG display --- and miles to empty does still get affected with the idles.

 

[AnthonyA1234]

My VW Beetle Turbo does that, if stopped the current MPG display Ø and trip avg MPG display --- and miles to empty does still get affected with the idles.

That makes more sense to me I don’t see the advantage of seeing that information during idle

 

[jhammy49]

unless it figures in idle time you won’t have an accurate average. Do you think it doesn’t use gas when your idling?

This. Also why ford has added the auto eng cutoff when at full stop. To save gas which does help your overall mpg.

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