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pgwerner

Just Bought '05 Corolla - Mileage Is Awful!

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Very interesting....Yet another innovative technological accomplishment that never made it into the main stream. But, it kinda begins to validate my hypothesis on a WAI.

Warmer air = more combustible = less fuel required

 

Now.....Please correct me if I'm wrong but in today’s cars timing is controlled by the ECU. Therefore, if you were to increase the intake air temp altering the point of detonation the cars ECU should automatically adjust.

 

Like what a knock-sensor does to adjust for different fuel octanes.

:rolleyes:

To a certain point - the problem with Hot Vapor setups is that the fuel mix will autoignite regardless to ECM control and timing (unavoidable hot spots in the engine). In the case of moderate temperature increases - the ECM can control timing to a certain point to help avoid the issue.

 

Also to add more to your hypothesis on warmer temps - true less fuel is required which also equals less power. The problem is finding a happy medium - difficult in an uncontrollable enviroment like everyday driving.

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Indeed, I do notice slightly a better mpg during late summer than in winter, but the difference is very slight, almost negligible- around 1mpg difference.

 

oh i guess the A/C factor comes in...

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Jacek writes:

 

I'm not the original poster but your advice is insulting. If you reread the very first post, you will find the poster used to get 30mpg in old Corolla and is getting 24mpg in the new one WITH THE SAME DRIVING STYLE.

 

My corolla also has suboptimal MPG REGARDLESS of driving style. I get 27mpg in city with regular driving and 28mpg with super duper granny driving (keeping RPM under 2000). I also get disapointing 30-31mpg on hwy. So, I'm very sympathetic to the original poster's cause as I went through the same disappointment. The car now has 30000 miles and it's the same, so don't count on improving. BTW, I keep tires inflated to 36 psi and observe all precausions to save fuel.

 

Clearly, some corollas are not as efficient as others and it would be nice to discover the root cause. Blaiming on the driver is contraproductive.

 

Thanks for the support Jacek. I pretty clearly stated that my driving habits haven't changed since I had my previous vehicle, which I was getting 30 mpg with. Since I started this thread, I've been checking everything I can on the vehicle. The air filter is clean. One of the tires was strongly underinflated, and I hoped that would be the root of the problem - after making sure all tires were at 30 psi (the recommended inflation, and what I kept the tires on my previous vehicle at), the mileage picked up a little. Its now more like 26.6 mpg, still not nearly what it should be. If anything, '05 Corollas are supposed to get better mileage than '95 ones (like my old vehicle).

 

Interesting to read that this is a known problem with some '05 Corollas - I wish I'd known that before I bought one! If I'm stuck with one of these, is there any known fix?

 

I've been talking to the service department of the dealership - complete stone wall with these people. The mechanic there claims the only thing internally that could throw off the mileage would be the emissions system, and that that would automatically set off the "check engine" light. The only other thing they held out was that they could run a diagnostic (at my expense unless a warranty-covered problem turned up.) I've called Toyota Warranty service - they suggested that the vehicle may have been driven wrong during the "break in" period and that, if possible, the dealership mechanic might be able to erase out the stored info on the car's computer, and I could then break it in again. Does that sound like a good solution?

 

Its a nice car and I got a really good price on it (a few thousand below MSRP, which also now makes me suspicious), but one of the reasons I chose a Corolla was for the mileage, and it sucks to see that's not up to snuff.

 

Peter

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Sometimes - you just have to drive the hell out of the car and see what happens.

 

Take my Matrix - usually get anywhere from 22-23MPG city to 25-27MPG highway. Best I got for the longest time was 28MPG on a 300+ mile trip. Always used premium (calls for it - XRS model), pumped the tires up to 44PSI (Goodyear RS-A), no mods to the car at all - all OEM. Everything was in good shape, run synthetics, clean plugs, etc.

 

Recently, I had to make several trips back and forth to and from a job site - we were on a compressed schedule and time was something we were running out of quickly. Ran four 200 mile legs - first set of two, averaged about 65 MPH - didn't want to get a ticket and drove easy, stayed out of lift (those with VVTL-i will understand) - first tank 26.3MPG (about what I usually get on my normal commutes). Second set - didn't give a darn, wanted to get home. Averaged 90MPH - hit lift in the first two gears consistently - tach hovering around 4-5K rpms for most of the trip, filled up at the same station and same pump. Got 32.7MPG that leg???? Weather was fairly consistent - started runs in the morning, ended in the evening - temps didn't vary too much, humidity was pretty stable all day, little to no wind.

 

Next couple of days - the fuel economy for my commutes, regardless of how I drove, improved a little bit (2-3 MPG better). This weekend, filled up - mileage is back down again, 24.5 MPG, my wife doing most of the driving there. I had my OBD logger connected - no huge changes in the fuel trim trends, everything seems to make sense - I'll study them in more detail this weekend to figure it out.

 

My Corolla - doesn't matter if you drive it like Granny or drive it like you stole it - 30-32MPG every time.

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I've called Toyota Warranty service - they suggested that the vehicle may have been driven wrong during the "break in" period and that, if possible, the dealership mechanic might be able to erase out the stored info on the car's computer, and I could then break it in again. Does that sound like a good solution?

 

Its a nice car and I got a really good price on it (a few thousand below MSRP, which also now makes me suspicious), but one of the reasons I chose a Corolla was for the mileage, and it sucks to see that's not up to snuff.

 

Peter

 

It is true that the ECU learns how you drive it and adjust the tranny shift points and possibly other thing to suit your driving style, but it doesn't take long to relearn a change, so the claim that the car needs to be "broken in" again makes no sense to me. I reset ECU/TCU in my subaru a few times with no impact on MPG. Didn't try in toyota though.

 

This brings another issue whether improper brake in (in mechanical sense) in the first hundreds of miles can permanently harm the engine in a subtle way and affect MPG.

 

When I took a delivery of my "brand new" corolla, it had 500 miles on it as it was a dealer exchange. I was furious about it but accepted after all as it had hard to find options. It was probably abused with high speed hwy driving.

Edited by friendly_jacek

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I've called Toyota Warranty service - they suggested that the vehicle may have been driven wrong during the "break in" period and that, if possible, the dealership mechanic might be able to erase out the stored info on the car's computer, and I could then break it in again. Does that sound like a good solution?

 

Its a nice car and I got a really good price on it (a few thousand below MSRP, which also now makes me suspicious), but one of the reasons I chose a Corolla was for the mileage, and it sucks to see that's not up to snuff.

 

Peter

 

 

It is true that the ECU learns how you drive it and adjust the tranny shift points and possibly other thing to suit your driving style, but it doesn't take long to relearn a change, so the claim that the car needs to be "broken in" again makes no sense to me. I reset ECU/TCU in my subaru a few times with no impact on MPG. Didn't try in toyota though.

 

This brings another issue whether improper brake in (in mechanical sense) in the first hundreds of miles can permanently harm the engine in a subtle way and affect MPG.

 

When I took a delivery of my "brand new" corolla, it had 500 miles on it as it was a dealer exchange. I was furious about it but accepted after all as it had hard to find options. It was probably abused with high speed hwy driving.

 

I often wonder the same about my Mazda3. The salesman had to bring the car up from another dealership 60 miles away.. and it was driven by his (salesman's) son. Why it wasn't put on a truck, I don't know.

 

Anyway, the transmission (auto) on the car just doesn't want to behave on a consistent basis. It feels very sloppy.. does a lot of hunting on upshifts. Sometimes I think it could be due to the punk kid running the hell out of the car on it's first few miles. I have reset the ECU a few times, and it helps, but it shortly reverts back to misbehaving.

 

It's nothing detrimental that I can prove wrong... just a massive amount of complaining on my part. it does make the drive less enjoyable, though.

 

And that's one of many reasons why I will never buy an automatic again, if I can help it.

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I've called Toyota Warranty service - they suggested that the vehicle may have been driven wrong during the "break in" period and that, if possible, the dealership mechanic might be able to erase out the stored info on the car's computer, and I could then break it in again. Does that sound like a good solution?

 

Its a nice car and I got a really good price on it (a few thousand below MSRP, which also now makes me suspicious), but one of the reasons I chose a Corolla was for the mileage, and it sucks to see that's not up to snuff.

 

Peter

 

 

It is true that the ECU learns how you drive it and adjust the tranny shift points and possibly other thing to suit your driving style, but it doesn't take long to relearn a change, so the claim that the car needs to be "broken in" again makes no sense to me. I reset ECU/TCU in my subaru a few times with no impact on MPG. Didn't try in toyota though.

 

This brings another issue whether improper brake in (in mechanical sense) in the first hundreds of miles can permanently harm the engine in a subtle way and affect MPG.

 

When I took a delivery of my "brand new" corolla, it had 500 miles on it as it was a dealer exchange. I was furious about it but accepted after all as it had hard to find options. It was probably abused with high speed hwy driving.

 

I often wonder the same about my Mazda3. The salesman had to bring the car up from another dealership 60 miles away.. and it was driven by his (salesman's) son. Why it wasn't put on a truck, I don't know.

 

Anyway, the transmission (auto) on the car just doesn't want to behave on a consistent basis. It feels very sloppy.. does a lot of hunting on upshifts. Sometimes I think it could be due to the punk kid running the hell out of the car on it's first few miles. I have reset the ECU a few times, and it helps, but it shortly reverts back to misbehaving.

 

It's nothing detrimental that I can prove wrong... just a massive amount of complaining on my part. it does make the drive less enjoyable, though.

 

And that's one of many reasons why I will never buy an automatic again, if I can help it.

 

It isn't just your Mazda3 with that problem. Mine was delivered to the dealer I bought the car from and it had 3 miles on it when I purchased it. The fully automatic mode of the transmission on the 3s is retarted, and the 3i is the same way. I refuse to use full auto anywhere since I have the option of semi auto on my 3s. Semi auto with me commanding the transmission yields 100% smoother, faster, and more percise upshifts than full auto. Me thinks Mazda didn't tune the 4 speed shift points correctly for either engine and so no matter what you drive you get a compromise that yields crappy results if you drive in full auto.

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I was somewhat unforgiving to my corolla when I first bought it brand new with 3 miles on it. Although, 90 percent of the time during the first 1000 miles I let the car shift under 3000 rpm. As for the rest 10%, I went up to 5000 at the most.

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I was somewhat unforgiving to my corolla when I first bought it brand new with 3 miles on it. Although, 90 percent of the time during the first 1000 miles I let the car shift under 3000 rpm. As for the rest 10%, I went up to 5000 at the most.

Should not have hurt it - cars are meant to be driven. The Corolla's engine doesn't have a reputation to need a careful break-in like some Mitsubishi (ie. EVO) and some European imports (ie. BMW M3 and Audi RS6).

 

I drove my Corolla (17 miles on clock) on a 500 mile trip (was in the process of moving) the very day I picked it up - that was my "break-in". No problems with fuel economy or oil control, just EVAP and emissions issues.

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All the problems (especially low MPG) with the newer Corollas makes me less likely to purchase one in the future. I think I will stick with my 7th generation ones that get almost 30 MPG consistently. I don't want to spend lots of $$$ on a new car that does not even get the MPG that I am getting now with a car that is paid for.

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I am hoping with the technological advances and also the ever increasing cost of fuel that something driveable will come along soon that is also affordable. I plan on saving my pennies until my car will no longer be viable as a continuing source of transportation for me. I am seriously considering a Hybrid or electric vehicle that is not 100% dependent on fossilized fuel for propulsion. I have nothing against Toyota, other than the poor fuel consumption and the looks of the newer cars, as well as the prices.

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I am hoping with the technological advances and also the ever increasing cost of fuel that something driveable will come along soon that is also affordable. I plan on saving my pennies until my car will no longer be viable as a continuing source of transportation for me. I am seriously considering a Hybrid or electric vehicle that is not 100% dependent on fossilized fuel for propulsion. I have nothing against Toyota, other than the poor fuel consumption and the looks of the newer cars, as well as the prices.

 

LOL, the best hybrids are made by Toyota. My next car has to be a plug-in Hybrid. Commuting on electric power, sweet.

 

BTW, I wasted some time on BITOG again. Found something interesting. One guy boasted geting 40+ MPG in Corolla while driving at moderately high altitude: 4700 feet and higher.

Interesting, I have disappointing MPG and drive exlusively at 0-1000 feet.

Any more inputs on the altitude thing?

 

http://theoildrop.server101.com/cgi/ultima...t=002831#000000

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I am hoping with the technological advances and also the ever increasing cost of fuel that something driveable will come along soon that is also affordable. I plan on saving my pennies until my car will no longer be viable as a continuing source of transportation for me. I am seriously considering a Hybrid or electric vehicle that is not 100% dependent on fossilized fuel for propulsion. I have nothing against Toyota, other than the poor fuel consumption and the looks of the newer cars, as well as the prices.

 

LOL, the best hybrids are made by Toyota. My next car has to be a plug-in Hybrid. Commuting on electric power, sweet.

 

BTW, I wasted some time on BITOG again. Found something interesting. One guy boasted geting 40+ MPG in Corolla while driving at moderately high altitude: 4700 feet and higher.

Interesting, I have disappointing MPG and drive exlusively at 0-1000 feet.

Any more inputs on the altitude thing?

 

http://theoildrop.server101.com/cgi/ultima...t=002831#000000

How can I lift my part of California about 4,000 feet? Maybe we can simulate the conditions in our cars to fool them into thinking they are at 4,700 feet? I would love to get more MPG.

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Filled up the other day, got 32MPG (city driving) - this is pretty much what I always get, I use 89 octane most of the time. Mine's a 01 LE.

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