mileage dropped from 26 to 19.
04-21-11, 11:00 AM
#1
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mileage dropped from 26 to 19.
The change is based on the info readout. I have had the engine looked at and told everything looks in good shape. So I filled up and took a 75 mile ride on the expressway and filled up again. So I had a good mileage calculation. It came out at 24 and the car info said 19. So it looks like the car measurement is in error. I don't know how the car does the measurement or if it uses the measurement in determining gas flow to the engine. Also, it is time for tires so I am probably losing 1 to 2 from the poor tires.
04-21-11, 11:22 AM
#2
Do you have a 330 or a 350?
04-22-11, 03:09 PM
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Thanks, everyone. I asked the dealership if a error in the functioning of the calculated miles per gallon had any effect on the engine and they said no. I'm not gonna worry about it. This car has always had great mileage. Once on a 700 mile trip to Maine I decided to drive very conservatively - 65 no or little passing. We got 29 mpg.
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04-24-11, 08:33 AM
#11
Forget the computer calculated mpg. Do periodic real mileage checks and compare them to see if anything changes as an indication that something needs attention. I got in the habit of checking almost every fill up. I noticed right away when it dropped a few mpg for no reason and I realized that it had to be because of winter gas formulation.
To be accurate you can't just fill up to the point the pump shuts off since there is wide variation in that. Top off to the same point each time--I go to a couple inches from the top of the filler tube. Assuming the pump metering is accurate this should give you very accurate results. Even if the miles are a tiny bit off (your odometer doesn't know about tire wear for example) the error will be the same each time and cancel out. Likewise if pump accuracy concerns you then just fill at the same pump when doing a mileage check. Again, while these things could cause a small error when comparing with other people when comparing with yourself at different times they will all have the same error so it's a valid comparison. The data gathered from driving through a full tank should be sufficient.
I have a 2008 RX350 AWD and I burn regular. I typically get 19-20 MPG with a mix of local and freeway (city area, not open road) driving. Open road freeway-only might give me 21 or a bit more. MPG will drop about 2 with winter formulated fuel.
Some day I may burn a few tanks of mid-grade to see if it's true that it improves MPG. It's said that the computers take time to adjust so one tank alone isn't enough. Performance is fine so the only reason I would switch permanently is if it offers a lower cost per mile and switching temporarily would be to gather data to see if it's true.
Steve
To be accurate you can't just fill up to the point the pump shuts off since there is wide variation in that. Top off to the same point each time--I go to a couple inches from the top of the filler tube. Assuming the pump metering is accurate this should give you very accurate results. Even if the miles are a tiny bit off (your odometer doesn't know about tire wear for example) the error will be the same each time and cancel out. Likewise if pump accuracy concerns you then just fill at the same pump when doing a mileage check. Again, while these things could cause a small error when comparing with other people when comparing with yourself at different times they will all have the same error so it's a valid comparison. The data gathered from driving through a full tank should be sufficient.
I have a 2008 RX350 AWD and I burn regular. I typically get 19-20 MPG with a mix of local and freeway (city area, not open road) driving. Open road freeway-only might give me 21 or a bit more. MPG will drop about 2 with winter formulated fuel.
Some day I may burn a few tanks of mid-grade to see if it's true that it improves MPG. It's said that the computers take time to adjust so one tank alone isn't enough. Performance is fine so the only reason I would switch permanently is if it offers a lower cost per mile and switching temporarily would be to gather data to see if it's true.
Steve
04-24-11, 09:50 AM
#12
Forget the computer calculated mpg. Do periodic real mileage checks and compare them to see if anything changes as an indication that something needs attention. I got in the habit of checking almost every fill up. I noticed right away when it dropped a few mpg for no reason and I realized that it had to be because of winter gas formulation.
To be accurate you can't just fill up to the point the pump shuts off since there is wide variation in that. Top off to the same point each time--I go to a couple inches from the top of the filler tube. Assuming the pump metering is accurate this should give you very accurate results. Even if the miles are a tiny bit off (your odometer doesn't know about tire wear for example) the error will be the same each time and cancel out. Likewise if pump accuracy concerns you then just fill at the same pump when doing a mileage check. Again, while these things could cause a small error when comparing with other people when comparing with yourself at different times they will all have the same error so it's a valid comparison. The data gathered from driving through a full tank should be sufficient.
I have a 2008 RX350 AWD and I burn regular. I typically get 19-20 MPG with a mix of local and freeway (city area, not open road) driving. Open road freeway-only might give me 21 or a bit more. MPG will drop about 2 with winter formulated fuel.
Some day I may burn a few tanks of mid-grade to see if it's true that it improves MPG. It's said that the computers take time to adjust so one tank alone isn't enough. Performance is fine so the only reason I would switch permanently is if it offers a lower cost per mile and switching temporarily would be to gather data to see if it's true.
Steve
To be accurate you can't just fill up to the point the pump shuts off since there is wide variation in that. Top off to the same point each time--I go to a couple inches from the top of the filler tube. Assuming the pump metering is accurate this should give you very accurate results. Even if the miles are a tiny bit off (your odometer doesn't know about tire wear for example) the error will be the same each time and cancel out. Likewise if pump accuracy concerns you then just fill at the same pump when doing a mileage check. Again, while these things could cause a small error when comparing with other people when comparing with yourself at different times they will all have the same error so it's a valid comparison. The data gathered from driving through a full tank should be sufficient.
I have a 2008 RX350 AWD and I burn regular. I typically get 19-20 MPG with a mix of local and freeway (city area, not open road) driving. Open road freeway-only might give me 21 or a bit more. MPG will drop about 2 with winter formulated fuel.
Some day I may burn a few tanks of mid-grade to see if it's true that it improves MPG. It's said that the computers take time to adjust so one tank alone isn't enough. Performance is fine so the only reason I would switch permanently is if it offers a lower cost per mile and switching temporarily would be to gather data to see if it's true.
Steve
04-24-11, 12:03 PM
#13
Forget the computer calculated mpg. Do periodic real mileage checks and compare them to see if anything changes as an indication that something needs attention. I got in the habit of checking almost every fill up. I noticed right away when it dropped a few mpg for no reason and I realized that it had to be because of winter gas formulation.
To be accurate you can't just fill up to the point the pump shuts off since there is wide variation in that. Top off to the same point each time--I go to a couple inches from the top of the filler tube. Assuming the pump metering is accurate this should give you very accurate results. Even if the miles are a tiny bit off (your odometer doesn't know about tire wear for example) the error will be the same each time and cancel out. Likewise if pump accuracy concerns you then just fill at the same pump when doing a mileage check. Again, while these things could cause a small error when comparing with other people when comparing with yourself at different times they will all have the same error so it's a valid comparison. The data gathered from driving through a full tank should be sufficient.
I have a 2008 RX350 AWD and I burn regular. I typically get 19-20 MPG with a mix of local and freeway (city area, not open road) driving. Open road freeway-only might give me 21 or a bit more. MPG will drop about 2 with winter formulated fuel.
Some day I may burn a few tanks of mid-grade to see if it's true that it improves MPG. It's said that the computers take time to adjust so one tank alone isn't enough. Performance is fine so the only reason I would switch permanently is if it offers a lower cost per mile and switching temporarily would be to gather data to see if it's true.
Steve
To be accurate you can't just fill up to the point the pump shuts off since there is wide variation in that. Top off to the same point each time--I go to a couple inches from the top of the filler tube. Assuming the pump metering is accurate this should give you very accurate results. Even if the miles are a tiny bit off (your odometer doesn't know about tire wear for example) the error will be the same each time and cancel out. Likewise if pump accuracy concerns you then just fill at the same pump when doing a mileage check. Again, while these things could cause a small error when comparing with other people when comparing with yourself at different times they will all have the same error so it's a valid comparison. The data gathered from driving through a full tank should be sufficient.
I have a 2008 RX350 AWD and I burn regular. I typically get 19-20 MPG with a mix of local and freeway (city area, not open road) driving. Open road freeway-only might give me 21 or a bit more. MPG will drop about 2 with winter formulated fuel.
Some day I may burn a few tanks of mid-grade to see if it's true that it improves MPG. It's said that the computers take time to adjust so one tank alone isn't enough. Performance is fine so the only reason I would switch permanently is if it offers a lower cost per mile and switching temporarily would be to gather data to see if it's true.
Steve
end of the day, once it clicks, stop pumping.
04-25-11, 05:22 AM
#14
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Its really not a good idea to put anymore fuel in your tank once the pump clicks for the first time (unless you know it made a mistake and you are only half full). the reason for this is that you have a charcoal canister for emission purposes. by filling up too much you risk the chance of putting fuel directly into that canister and other lines where it shouldnt be. this can then result in giving you a check engine light or worse, making you replace parts.
end of the day, once it clicks, stop pumping.
end of the day, once it clicks, stop pumping.
04-25-11, 06:53 AM
#15
Lexus Champion
Its really not a good idea to put anymore fuel in your tank once the pump clicks for the first time (unless you know it made a mistake and you are only half full). the reason for this is that you have a charcoal canister for emission purposes. by filling up too much you risk the chance of putting fuel directly into that canister and other lines where it shouldnt be. this can then result in giving you a check engine light or worse, making you replace parts.
end of the day, once it clicks, stop pumping.
end of the day, once it clicks, stop pumping.
Well, that means I`m in deep S hit! Because I got gas in jersey yesterday,and they pump for you over there. The attendant filled quite a few clicks after it shut off.
