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2007 and newer Chevrolet Tahoe and GMC Yukon

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Comments

  • tidestertidester Member Posts: 10,059
    I am a little uncomfortable with them 'playing' with a 47,000.00 truck that does not belong to them.

    I think they are just being a little too colloquial and simply mean that they will try to determine whether adjustments can be made to get V4 to work right. Clearly, they cannot make that determination over the phone.

    tidester, host
  • nosbor77nosbor77 Member Posts: 40
    There's nothing wrong with your Tahoe. There's just something wrong with Chevy's sales tactics. Most of their sales force don't know what thier fuel management does. If you apply gas, it will run in V8 mode. When you let your foot off the gas, it drops into v4 mode. Very misleading from their advertising. I say it's false and a joke. I've never been concerned about my mileage when I'm not applying gas. I doubt anybody else is. It will probably save you fractions in mileage compared to before.

    Your milage is normal. I was getting around 13.8 when I bought mine. Up until 3000 miles, the best i saw on highway were 19 at optimal spds like 60mph. Also, you have to BABY it to get good gas numbers. No driving over 2000 rpms. Also, most areas are using 10% ethanol in gas. This will result in worse milage b/c ethanol has fewer BTUs. ie less efficient just burns cleaner. The axle ratio you have could make a diff too. Not sure.. The mileage I reported above in my last posting was new to me. It improved when I hit 3000 miles. These #s are only obtainable when criusing on flat road. Don't expect them around town. Basically meaning stop and go driving. Expect your 13.8 or less around town. Yep, I'm impressed by the mileage I get on hwy. But they should be forced to get on TV and explain to everyone that their fuel managment system is a joke. When I didn't see it come on during the test drive, I was told that I had to drive it longer on the hwy to see it come on. HA.. that man should be fired.
  • jmaynardjmaynard Member Posts: 37
    Thanks for the insight. I too was fooled, not only ny the advertising but by the mass amounts of litrature that are published on the subject of this technology. It clearly states that the V8 running at a steady speed is only utilizing about 15% of it's available power and that in V4 mode it wold be about 80% utilized. Now, that would indicate that in V4 mode 10-15% more power would be available which would be more than enough to support the vehicle during highway non-steep incline driving. My experience is that it only goes into V4 in a decelleration mode. ANY eccelleration, even attempting to hold a steady speed on flat road or downhill results in V8 mode enabled. This just does not seem right. I am going to take the vehichel to the dealer and get them to show me how this system interacts with the vehicle. If someone programmed it, it can be fixed. It is just a matter of getting to the correct person. I'll let you know if I have an success.
  • junglegeorgejunglegeorge Member Posts: 129
    What gear are you running, 3:73 or 4:10 - I have found that I need to run 2400 RPM or better to activate the V-4 mode on level or slight up-hill conditions, I can accomplish this by either fooling the truck using the tow mode, or exceeding 75 - 80 MPH, at these speeds I am not saving anything, but it does run in V-4 mode, even up-hill. I am tying to prove that the 4:10 gear is a better choice, it seams that the drivers who opted for the 4:10 choice are reporting better MPG. thanks George
  • jmaynardjmaynard Member Posts: 37
    I don't remember from the sticker. I believe the 3:73. I am a little careful topping the 80 mark as the truck is still under 500 miles and the police just don't seem to understand :surprise:

    I suspect that if you can 'fool' it then it can be tuned or reprogrammed. After I get to the dealership, I suspect I already know their answer, I will report back here. I am willing to be the squeeky wheel, but if I do have to go the GM route it I will need the support of a lot of other drivers. I have found through other venues that grass roots movements against big companies DO work. If we can garner enough support e CAN grab media attention and get the numbers that were promised to us.

    After I get back from the dealership I will make my private email address available to everyone to see how much support we really have.
  • 73shark73shark Member Posts: 325
    Show them a copy of this which clearly states "In situations where extra power is not needed, such as cruising down the highway on level roads, Active Fuel Management deactivates four of the eight cylinders with seamless precision." :confuse:

    http://www.chevrolet.com/pop/tahoe/2007/vortec5300_en.jsp

    Good luck!
  • jmaynardjmaynard Member Posts: 37
    I suppose that 'level' is relative. For me - is level, for Gm it appears that \ is level. :sick:
  • rockman59rockman59 Member Posts: 250
    Your computer should be able to be reprogrammed. This is from the GM advertising regarding 4/8 engines:
    "The powerful 32-bit engine control computer triggers cylinder deactivation based on inputs from vehicle sensors —making deactivation virtually undetectable." Either the sensors are sending the wrong info or the programming is not correct for info being fed in.

    There are a lot of complaints coming in from all over the country on this matter. GM better stand up and take care of business on ths one.
  • tony20fantony20fan Member Posts: 30
    I, too, am disappointed in my gas mileage. I have not reset the DIC computer and am getting 13.2 mpg. However, I love my new Tahoe. Having had the first generation 4 door Tahoe (a '96), a 2000 (when they updated the body), a 2003 (Z71 model) and now my awesome 07, I see great improvements - both mechanically and asthetically. When it comes right down to it, I bought it because of the new body style, features and size. It's the perfect size for my family. Sure, I could have bought the Expedition, but I didn't want a Ford product. I have had wonderful luck with all my Tahoes and please, don't you just feel COOL when you're cruising down the road? I truly am sorry for all who bought for the gas mileage and are not getting the gas mileage advertised but this is a large vehicle with a lot of horsepower. I didn't buy if for the fuel efficency - if I did, I'd have waited for the hybrid. I just love the look, feel and dependability of my new Tahoe. That's gotta be good for something... :)
  • jmaynardjmaynard Member Posts: 37
    I WAS waiting for the hybrid, until Gm decided to pull it in favor of this Active Fuel Management. This is also my 3rd Tahoe and by far the best ride, most comfortable and coolest body style of any of the previous ones. My first one, a 1999 2 door version, was really sharp for it's time.

    I specifically justified the ability to upgrade based on the fuel savings. At almost 3.00 per gallon every MPG counts. If GM advertises that they can make this easier on me by running this beefy V8 on just 4 cylinders during cruising then I expect them to live up to that promise. It's all about getting what they sold me.

    If I sold you a ticket to Rio and when the plane landed you were in Alaska wouldn't you be upset. Sure, both areas have outstanding beauty and are really nice vacation spots, but you paid for a beach vacation not a glacier one. I want my beach vacation, and so should everyone else. :)
  • tony20fantony20fan Member Posts: 30
    OK, you got me. I wouldn't want to go to Alaska if I was planning on Rio - and I wouldn't have packed the right clothes!! Good analogy. I guess I am just resigned to the fact that I'm not going to get better gas mileage and there's not much I can do about it. GM won't. True, it's disappointing but I think the best thing I can do is enjoy the car and hope gas prices drop. Oh, and hope I didn't jinx the reliability by actually voicing my satisfaction. That'd be just my luck... :surprise:
  • jerrywimerjerrywimer Member Posts: 588
    They didn't pull the hybrid you say you were waiting on in favor of AFM. AFM (formerly called DOD) was demonstrated on a Malibu 6 cylinder a couple of years back. GM announced it before anyone else produced a vehicle with similar technology. Then GM sat around while both Honda and Dodge released the first vehicles actually using a form of it. GM announced the two mode hybrid full sized SUVs more recently (like less than a year ago) and the plans are still on for those.

    Both forms of tech are separate developments. While the hybrid system can work with the AFM engines though- the hybrid part is the transmission. And both have had their own development / production schedules. The production of one hasn't caused the other to slip in scheduled release either.

    So stop kidding people that you were waiting for one of those "hybrid" Tahoes. Because if you really were you would know that they are and always have been due up in roughly a year..
  • nosbor77nosbor77 Member Posts: 40
    I'm behind you 100%.. I feel terribly missled.
  • jmaynardjmaynard Member Posts: 37
    On the hybrids, I got first hand information from a local dealer who actually participated in Detroit at this years annual meeting and they were told, in very clear terms, that the hybrid had been shelved and would not be out until 2009 or 2010. I didn't believe him either because I had read on GM's web site a few weeks before that they it was in development. I went back to the web site and low and behold, no mention of the hybrid existed anymore. They pulled it from the site.

    Seems that GM is holding back. I suspect that the margin in the hybrids is a little lower and the costs to recoup the re-machining of the Arlington plant exceeds what they have invested in infrastructure at this time due to lagging sales of full sized SUV's. That's only my theory, but it would make sense. My theory would suggest that they are trying to use the coolness of the new Tahoe to drive sales to the point that they wold not have to recoup costs but could actually pay cash for the remachining (is that word?).

    But to sum up, the hybrid will not be out this year or next. The only thing I see changing that would be if Ford released one before then. Even with the hybrid, if it performs like the current fuel managed units the electric motors would hardly ever kick in resulting in just as poor gas milage as we are experiencing now. The fuel management system must be corrected for any of these technologies to work and be effective.
  • dsquaredsquare Member Posts: 6
    I have A 07 LTZ 4wd with 4:10 rear always run in 2wd. My MPG is around 13.2. We tried everything, baby the gas, coast downhill, tow mode, no a/c, except bringing it back to dealer for reprograming. I just don't believe that others are getting good average mileage. I live in Los Angeles and it is probably fuel mixture and all the stop and go traffic.
    but I did expect more than I am getting. has anyone had the reprograming yet that may help the MPG? :lemon:
  • cecookcecook Member Posts: 23
    Tony97gt,
    Chrome 22" rims look great on the 07s. There aren't any major hardware changes to make. The tire pressure sensors need to be reused with the new tires. Realize that the new wheels and tires will change most of your calculations on your d.i.c.. Most dealers I have talked to cant correct the readings but some aftermarket programmers can. It also depends on the tire size you go with as to how off the readings will be, like speedometer wise. I don't know how to post pics in this forum but you can email me and I will reply with some.
    Collins
  • jmaynardjmaynard Member Posts: 37
    OK, I visited the service center this morning and as I expected they could not find a problem with the programming and there were no 'codes' showing up. From all they can tell, everything is working to spec. Now, here is how things happen at GM. It takes multiple complaints to get resolution. I am convinced that GM has the ability to improve our mileage but does not, for whatever reason. Perhaps it is to make a hybrid, when available, a more attractive upgrade for us. I will place my formal complaint to the GM call center. I employ all of you ot there to do te same. If you are due for a service, have the service department check the V8 to V4 DOD for possible defects. Only after a suffecient number of complaints come in will GM look into the issue. I will keep up the pressure but I alone cannot make a difference. I need everyones help. YOU have to complain also. YOU have to tell Gm that they need to live up to the marketing that they use to sell vehicles. I will also be looking into what it will take to get media coverage about this. If anyone knows someone in the industry, mention it to them. If we can get them on our side, they can get to people that have yet to find their way to this message forum. Talk to other Tahoe owners and let them know that they need to complain.
  • tuscotoddtuscotodd Member Posts: 50
    I just made a 700 mile trip. First leg was with the cruise set at 69mph, filled up with non-ethanol added gas. Had the AC on low and averaged 20.1 over 360 miles. For the second leg I had the cruise set at 74mph filled up with 10% ethanol 87 octane and had a light head wind. I averaged 17.6mpg. The only changes I have made to my LT3 are a Zoomer's cat back exhaust system. I have the 17" wheels and 4.10 gears, so I am spinning in excess of 2000 rpm on the expressway.
    Other than the exhaust, I think my other advantage may be that I now have 6700 miles on mine. I have noticed that I have been able to drive more and more "spirited" and have been getting better and better milage as the miles have clicked off on the odometer.
    Just some food for thought. :D
  • jmaynardjmaynard Member Posts: 37
    That sends hope to some of us. the only thing that bothers me is that you have the 4.10 gears and mine is the 3.42. From what other are reporting I, as well as many others, may have made a mistake in our purchase. It appears that the programming is tuned to the 4.10 gearset which would explain why the rest of us are getting sucky mileage.

    I too have noticed some improvement as I drive further, but still nowhere where it should be.

    Thanks for the information. BTW: did you happen to watch how much the V4 became active while you were cruising? This is the part that I am furious about.
  • 73shark73shark Member Posts: 325
    I agree. Just got my back from service and they said my 07 LTZ was operating per spec and said on a section of level interstate was running in V4 mode. I pointed out that when I traveled in the opposite direction on that same "level" stretch, it was in V8 mode. No answer. Will try the Chevy hotline.
  • p356ap356a Member Posts: 3
    I know this has been discussed before but has anyone come up with an effective way to remove the air bag warning stickers from the fabric material on the 2007 Yukon. :cry:
  • tuscotoddtuscotodd Member Posts: 50
    "Thanks for the information. BTW: did you happen to watch how much the V4 became active while you were cruising? This is the part that I am furious about."

    jmaynard,
    With the cruise set at 69 it was spending a lot of time in V-4, I would say it was somewhere between 70-80 percent of the time. With the cruise set at 74 and the light head wind, it was spending notably less time - probably more around 20-30%.
    Hope that helps! :D
  • highsheriffhighsheriff Member Posts: 11
    tuscotodd, what rear end do you have in your tahoe?
  • tuscotoddtuscotodd Member Posts: 50
    highsheriff -
    I have 4.10's in mine (it is a 4x4 as well).
    Hope that helps!
    :)
  • eliaselias Member Posts: 2,209
    folks, when your tahoe is coasting at ~30mph or more - with your foot off the gas- there is zero fuel being injected into the cylinders.
    so in those coasting-in-gear situations, it won't matter if the ignition is in "4" or "8" mode at that time - because there is no fuel to burn. V0 mode!
  • jmaynardjmaynard Member Posts: 37
    Only if you turn off the ignition. Even during coasting the engine burning fuel at idle consumption, which would require 50% more fuel in V8 mode than in V4 mode. If it were burning 0 fuel it would shut the engine off and you would get the just ran out of gas feeling as you drifted to a stop.

    This is why the V4 mode is so important. Even while coasting you are using fuel, 2 times as much if the engine is in V8 mode! :surprise:
  • jmaynardjmaynard Member Posts: 37
    That helps a lot. It is even more of an indication that there is ONE program for both the 4.11 and the 3.42 and GM programmed it using the 4.11. I think all the 3.42 owners need to revolt. We should be getting the same advantage no matter which rear end we happen to get stuck with. I guess I could ask Chevrolet to replace mine with the 4.11 for free and see what they gets me.
  • nosbor77nosbor77 Member Posts: 40
    Yes. It does require fuel just to idle. But that amount of fuel is a fraction of the amount required when accellerating. That's why dropping to V4 mode when idle is meaningless to me. It won't make a large impact on fuel consumption. I was under the impression it dropped to v4 under mild acceleration. In other words, if you're cruising at 75, 4-6 cylinders should be sufficient to slowly bring you up to 80.. Now, quickly accelerating from 65 to 80 would require more HP than v4 could put out hence kicking into v8 mode..

    All I see is v4 coming on when no accelleration is underway. The individual seeing V4 coming on during cruise control is only seeing V4 come on when the computer is not accellerating. The engine is idle at this time. When V4 is on during engine idle, that minimum amount of fuel pumped into the cylinder to keep it idling is still being pumped into all 8 cylinders.

    A certain % of chevy's consumers don't understand this and are going to be satisfied with just seeing V4 mode show up on thier console. Chevy isn't dumb and they obviously know this. Maybe their sales force don't know this, but engineers and decision makers at Chevy do. They are satisfied with this. This was their intention. This was their quick fix to quickly coerce people into feeling comfortable buying a large SUV when gas prices are so high. They know what they are doing and it is 100% intentional. They know that if a concumer does catch on, they will be stuck with the Tahoe and drive it long enough until they feel comfortable selling it. To Chevy, its a sale and on paper its a sale. That's all they care about. If american companies were out to make the best vehicle possible they'd be building them with the reliability of Nissan and Toyota. They all have the same engineers with the same capabilities.
  • nosbor77nosbor77 Member Posts: 40
    I think elias is speaking of anything beyond the min amount of fuel required to keep the engine running idle. All cylinders will get this, even when in v4 mode.
  • gcmartingcmartin Member Posts: 19
    Those who are reading this thread need to understand that when a car is decelerating that the engine of the car must do a certain amount of engine braking. This happens in all automatics similar to what you do in a manual shift car. If you notice when you coast that the transmission will kick down as you reach lower engine speeds. With the DOD on the Tahoe it decelerates in V4 mode until you reach 30 to 35 mph and as the transmission downshifts to third then second when V8 mode comes on under 25 mph. Finally, the transmission will shift into first upon coming to a complete stop. I have noticed that the my Tahoe will shift into second when starting off and then to first under heavier load. This is probably some kind of economy mode that the literature does not explain.

    This is confusing for many as they may think that the engine does nothing on deceleration. This is not the case. This is one of the reasons that hybrids are so attractive. They use the deceleration to generate electricity to store in the batteries thereby taking energy from braking from what is usually wasted in heat(brakes) and/or fuel(combustion engine autos).

    To have a real V0 mode auto whould be the most attractive and efficient. This could be done by making a hybrid that used braking force to generate electricity stored in batteries which would run an electric motor that would work under light load saving the gasoline engine for high load. None of the hybrids made now are as efficient as they could be. The most efficient would run the air conditioner and car in heavy traffic, stop lights, cruising and stop and go situations thereby saving fuel for only heavy demand situations. This formula has been being used by diesel electric locomotives and ships for years. Battery technology is the key. Batteries are heavy, expensive and wear out. To get enough capacity with weight constraints for autos has just become possible in the last few years.

    I have done some long trips and the Tahoe/DOD system works very well on the highway with almost 19mpg. For short trips with a/c it is getting around 12.5mpg. This was to be or should have been expected. The engine is 5.3 liters with 300HP. That's a big motor. I have been babying the accelerator. I don't think I've floored it since I bought it. In comparison, my 2004 Land Rover Discovery with a 4.6 liter engine was getting 11mpg in short trip driving. So I will take the 12.5mpg any day.

    Hopefully, GM will release a software upgrade that will improve the V4 mode operating efficency. I do believe that it could stay on more. Especially during highway crusing. Just be happy you didn't buy an Escalade or a Denali which have the 6.0/6.2 liter engines. I imagine they are only getting 10mpg or less in the city!

    I just wnet and looked on the Escalade and Yukon sites. Evidently, Escalade/Yukon owners are not as budget conscious as us Tahoe owners. No threads about gas mileage. Maybe they're just so awful that they don't want to think about it!

    Check out the burned up Denali in the thread on Yukons! Wonder what went wrong with that one?
  • junglegeorgejunglegeorge Member Posts: 129
    Does anyone know where to pick up a switched power source for accessories? With everything communicating on the LAN, I cannot seam to identify a switched circuit that I can power my detector with. Any help would be greatly appreciated. George
  • jmaynardjmaynard Member Posts: 37
    gcmartin, thanks for your input. From what you state, you have fallen victim to the problem but have not accepted it. The ONLY way Gm will fix this is if enough people complain. I am doing my part. Remember, admitting you have a problem is the first step in getting help!

    Don't accept that because they hand you all this power YOU are responsible for improper engineering and YOU should pay for it. This problem CAN be fixed and GM needs to step up to the plate. Please help by complaining. You have nothing to lose and everything to gain. I promise, they don't kow you well enough to hate you for complaining and the savings that you could recieve would go staight back into your bank account.
  • wlbrown9wlbrown9 Member Posts: 867
    Isuzu Trooper has what they call 'Grade Logic' that engages the transmission and engine for braking when coasting down down hills. I guess the idea is to keep from building up too much speed downhill. It works pretty well on my '00, even sometimes when I would rather it not downshift and bring the revs up and slow me down :-)
  • gcmartingcmartin Member Posts: 19
    I have accepted the problem and intend to complain when I go in next time for scheduled maintenance. I hope they will address the issue. Considering that you can program the computers on most cars or even buy performance chips which can increase horsepower, this may be an avenue for aftermarket companies to get into the act. I own a 2004 Subaru STI and I can hook my computer up with a programmer and remap the fuel injection with a download to match the intake and catback. Same holds true for my Kawasaki ZX-12R which has a Powercommander in it.

    It seems that GM could do that when the car was brought in for service. An example would be: Tahoe comes in for service and they download version 2.XX of DOD firmware to the car which addresses issues in V4/V8 mode.

    This seems like a logical step to expect. Maybe GM is not that advanced, but it would seem that they already have the capability and the Vortec DOD is in a continual state of fine-tuning.

    I already called customer service and formally asked about the possibility that a newer firmware could be downloaded at the dealership to address these issues, but I am not sure that it will be heard by the responsible parties.
  • jmaynardjmaynard Member Posts: 37
    Thanks gcmartin. I believe that they programmed the set that we are currently running using a vehicle with a 4.11 rear axel and even in that situation they took a safe approach to insure that we get the horsepower without a noticable mode switch. As I have stated, it is going to take numerous customer complaints from acorss the country.

    Thanks for raising a red flag where you are. Hopefully others will follow. I will be on the lookout for other 07 owners so that I can spread the 'love' to them.

    You are absolutly right. Someone will come up with an aftermarket chip or program, but if you are like myself, you wouldn't want to invalidate the warranty by installing one. I also leased my ehicle and the lease states no after market parts be installed.

    I agree that they should be able to do it when brougt in for service, the only problem is there is not a newer version available from GM. As far as they are concerned, noone is complaining so there must not be a problem.
  • mandingo214mandingo214 Member Posts: 1
    Just found this site, looking to see if anyone else was getting lousy mileage with their 2007 Yukons. I have a 2007 Yukon XL, with 4500 miles, 3.73 gears (I did not think 3.42 were available) and average about 14mpg. We took it on a 1600 mile trip and only averaged 16mpg. Our best tank, all highway, was 16.5. Our 2002 Yukon XL would average 18 on the same trip. Bummer.

    V4 mode comes on when coasting. Maybe a little when cruising at 60mph.

    The 2007s are a lot nicer than the old ones, I just wish the mileage would be as advertised. It really irks me that we took a step backwards, mileage wise, from our 2002 Yukon XL.

    The dealer service department tells me there are no codes, so there is nothing they can do.

    What number at GM are you calling to complain? I will certainly give them a call.

    Thanks.
  • rwernerrwerner Member Posts: 7
    My LTZ has made two trips from Atlanta to Indy by way of Cincinnati since I bought it in March it has 7k miles on it. On the trips I got as high as 19.5 miles per gallon doing about 5 mph over the speed limit. Also when using it to go to work in Atlanta traffic I can nurse 14 mpg out of it. I don't usually have the DOD up on the display but I'm ok with the mileage. Also I've been a dealer technician for over 40 years most with GM although not now. Over the years doing driveabilty work I learned that alot of the problems we had were software/programing related but found that GM would not update the program in the production year of the vehicle because they would have to recertify with the EPA. Im sure it's the same now. There is no valve action or fuel in the cylinders when in the V4 mode so has to help. At this time I have not seen anything in the aftermarket that will work on 2007 Tahoes as far as reprograming at this time. Let me know if I'm missing something.
  • sovereignmgmtsovereignmgmt Member Posts: 30
    It's been done and here it is.Nav Override
  • rockman59rockman59 Member Posts: 250
    At this time I have not seen anything in the aftermarket that will work on 2007 Tahoes as far as reprograming at this time. Let me know if I'm missing something.
    -----------------------------------------------------------
    I think the above reference was to reprogramming the engine computer, not the NAV system. But that NAV reprogram kit looks pretty cool.
  • 73shark73shark Member Posts: 325
    Hope this comes with a flashing strobe light on the roof so everyone can get out of the way!
  • sovereignmgmtsovereignmgmt Member Posts: 30
    You are missing it completly. This is a hack/bypass for the Nav system NOT the engine computer

    This will allow you to play a video on the front screen as well as programing the Nav while moving.
  • rockin_ltzrockin_ltz Member Posts: 61
    OK...So who's gonna be the guinea pig on this one to see if it works and if so, how easy it was to install??

    I'm interested in this mod but don't want to be the first!!! :D
  • rockman59rockman59 Member Posts: 250
    To Sovereignmgmt: I thought you were replying to rwerner who was concerned with reprogramming his engine computer to increase his gas mileage. I understand that the hack/bypass for the Nav system is NOT the engine computer. Da!!!! I did go to the Nav sight and watched their little video. Very impressive....and all for $249.95.
  • sovereignmgmtsovereignmgmt Member Posts: 30
    It works great and it was a snap to install. In fact there is a video link on the install on there page.
  • deovindicedeovindice Member Posts: 11
    I'd consider paying that amount if the hack included the ability to use the built in phone system with my current provider and phone. This is one of my biggest beefs with the vehicle, the fact that they didn't put in bluetooth and opted to force you to use Onstar or Verizon.
  • nosbor77nosbor77 Member Posts: 40
    Check out this article on GM Flex Fuel

    http://autos.aol.com/article/hybrid/hub/_a/flex-fuel-fallacy/2006081513330999000- 1

    Maybe we can get AOL involved to do an article on their AFM fallacy
  • 73shark73shark Member Posts: 325
    That would make for an interesting article! Another problem with ethanol is that it takes more energy to produce than you get when you use it. :confuse:
  • catahoecatahoe Member Posts: 15
    Sorry thats just a rumor... Might have been true in the early days but not anymore
  • jay_24jay_24 Member Posts: 536
    The cost to produce is very much in question. Some say it costs more others say it costs less.
    Biggest issue currently is that most ethanol plants use the kernal of corn to make it. The next generation of ethanol plants will use the stalk, or grass, or other plant materials that are typically waste products today.
  • eliaselias Member Posts: 2,209
    hi! i really do mean that your vehicle uses zero fuel whatsoever when you are coasting in gear (foot off gas pedal!) - as long as rpm is above some minimum - 1000 or 1500 rpm maybe.
    this is the way fuel-injected vehicles have operated for at least 20 years - i not aware of *any* exceptions and would be awfully surprised if this new Tahoe is an exception.
    it would be counterproductive and wasteful for the ECM to pump any fuel during foot-off-gas/deceleration, as long as RPM is ~1000 or more.
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