2014+ Gas Mileage (MPG) Topic

[Ton J]

I have a big issue that has popped up. I just filled up with E85 and after running about 100 miles the mpg looks dismal. I will not know for sure until I run a few tanks through. The issue and I guess you could say bright side is that this 5.3 engine loves the E85 you have to really be careful with the gas pedal as people will be staring at you because the rear tires are spinning on the slightest take off. you must gain over 50 HP with this alcohol fuel. Is that just on E85

Is that just on E85 or both fuels. GM keeping a long stick away from issue. More reports are complaints are coming into dealerships about the drop in in MPG. Might get worse as it warms up. 60 degrees here yesterday and both meters are dropping to down in 14 mpg.

Edited March 16, 2014 by Ton J

[blckthree]

I have a big issue that has popped up. I just filled up with E85 and after running about 100 miles the mpg looks dismal. I will not know for sure until I run a few tanks through. The issue and I guess you could say bright side is that this 5.3 engine loves the E85 you have to really be careful with the gas pedal as people will be staring at you because the rear tires are spinning on the slightest take off. you must gain over 50 HP with this alcohol fuel.

Your fuel mileage will be lousy with E85, the savings there comes from the greatly reduced cost at the pump.

 

Mike

[strike1st]

Had to chime in on temp swings. Lol not to bash ya but we had 70 degrees the other day and snow within 24 hours. Thats an Indiana temp swing lol. It will effect fuel milage for sure.Sent from my LGL86C using Tapatalk

I understand that... But are you averaging 10 to 11 mpgs? THAT is what I'm bitching about...I assume some loss because of temp changes...But not to get anywhere near estimates, that's bull shit.

[Dnt]

Looks like so far the average has moved down about 3 mpg. I had a lifetime average of 18 mpg on 10% 87 octane so going to have around 15mpg on E85 if my guess is correct. Keep an eye on the fuelly site "MyFavTruck" in the 2014 GMC Sierra 1500 section. it will take several weeks to go through a few tanks and really check the drop in mileage to see how significant it is. I was just shocked that the HP change was that noticeable. Are the 6.2 engines Flex Fuel also? I would love to drive a 6.2 on E85 it should be well over 450Hp that is ground pounding LOL. If you were having a vibration problem and suspected the tires you could make them round with a couple of good burnouts VROOOOMMMM LOL

Edited March 16, 2014 by MyFavTruck

[Ton J]

Looks like so far the average has moved down about 3 mpg. I had a lifetime average of 18 mpg on 10% 87 octane so going to have around 15mpg on E85 if my guess is correct. Keep an eye on the fuelly site "MyFavTruck" in the 2014 GMC Sierra 1500 section. it will take several weeks to go through a few tanks and really check the drop in mileage to see how significant it is. I was just shocked that the HP change was that noticeable. Are the 6.2 engines Flex Fuel also? I would love to drive a 6.2 on E85 it should be well over 450Hp that is ground pounding LOL. If you were having a vibration problem and suspected the tires you could make them round with a couple of good burnouts VROOOOMMMM LOL

Ive had 305/40R22 Flaken on both of Tahoe and the last Silverado and it didn't affect the gas mileage if anything it was better the EPA. I think the longer they go the worse they get. 6.2 are do great from what my cousin showed me yesterday he getting above average. and he has 24' in tires and rims on his truck. So once again whats GM saying about this NOTHING.

[Ton J]

I understand that... But are you averaging 10 to 11 mpgs? THAT is what I'm bitching about...I assume some loss because of temp changes...But not to get anywhere near estimates, that's bull shit.

Its more then just Temp playing in on this. It will to a degree. Atoms slow down when its cold so it doesn't cause fraction and so you don't have much fumes. So when you have warm temp above 30 degrees atoms move faster and get more fraction and expanded faster. So if in theory what if the truck having to use more gas to get fraction between cylinders. that might account for lower mpg. So it could throw your gauges off because its reading alcohol per volume. and not mile per tank.

[Ton J]

Ive had 305/40R22 Flaken on both of Tahoe and the last Silverado and it didn't affect the gas mileage if anything it was better the EPA. I think the longer they go the worse they get. 6.2 are do great from what my cousin showed me yesterday he getting above average. and he has 24' in tires and rims on his truck. So once again whats GM saying about this NOTHING.

 

 

Looks like so far the average has moved down about 3 mpg. I had a lifetime average of 18 mpg on 10% 87 octane so going to have around 15mpg on E85 if my guess is correct. Keep an eye on the fuelly site "MyFavTruck" in the 2014 GMC Sierra 1500 section. it will take several weeks to go through a few tanks and really check the drop in mileage to see how significant it is. I was just shocked that the HP change was that noticeable. Are the 6.2 engines Flex Fuel also? I would love to drive a 6.2 on E85 it should be well over 450Hp that is ground pounding LOL. If you were having a vibration problem and suspected the tires you could make them round with a couple of good burnouts VROOOOMMMM LOL

Vibration is coming is not coming from the tire. I can tell you that. I test drove 4 trucks on lot and they all had the same problem. I think its either in linkage or steer housing.

[strike1st]

I'll try to get a pic of the dic today...lifetime average this morning was 10.6 mpgs at just over 900 miles. Yeah....I know not many miles...9 degrees this morning and once again after a few days in the upper 30's and low 40's my mileage is going backwards again...I was only at 13mpg in town to start with. running 89 octane 10% ethanol.

[CAtaylor]

*Strike1st* Something is definitely not right with your truck and I think you have every right to complain and want it fixed. I notice a small swing when the temp changes from freezing in the morning to 70's in the evening but nothing that would amount to what you are seeing. 1 to 1 1/2 mpg is the most I have seen. I have also had the fire recall update. Granted I do not live in sub 0 climate but this has been a rough winter for us as well with many days below freezing. I have 6" lift and running 35" tires and factory 3.42 gears; had calculated it comes out to 15.09 mpg for the 400 mile trip meter and 14.2 mpg over the last 2,299 miles. I took these before dropping the truck off at the gear change place the other day but the change did not happen. I wanted a good comparison for after I swap in the 4.56 gears.

Edited March 17, 2014 by CAtaylor

[Nofastcar]

I've got a double cab 4x4 with the 4.3. Only run through 3 tanks of fuel so far but according to the math I'm getting 15 ish. My last tank was only 14.9 but I had a little more city driving than usual. Gas milage is the only complaint so far with mine.

[Ton J]

*Strike1st* Something is definitely not right with your truck and I think you have every right to complain and want it fixed. I notice a small swing when the temp changes from freezing in the morning to 70's in the evening but nothing that would amount to what you are seeing. 1 to 1 1/2 mpg is the most I have seen. I have also had the fire recall update. Granted I do not live in sub 0 climate but this has been a rough winter for us as well with many days below freezing. I have 6" lift and running 35" tires and factory 3.42 gears; had calculated it comes out to 15.09 mpg for the 400 mile trip meter and 14.2 mpg over the last 2,299 miles. I took these before dropping the truck off at the gear change place the other day but the change did not happen. I wanted a good comparison for after I swap in the 4.56 gears.

Well guys I live in Arkansas and I got my truck in Sep 2013 and mpg was great til they did these updates and ive had several post about this issues for a while now. It doesnt get as cold south and reads have been the same no matter what fuel I use. But before I was over 16 mpg in the city and 24 mpg on hwy.

I getting better in my 2012 silverado and driving hasnt changed.

[iCryWheniGoPoop]

Well guys I live in Arkansas and I got my truck in Sep 2013 and mpg was great til they did these updates and ive had several post about this issues for a while now. It doesnt get as cold south and reads have been the same no matter what fuel I use. But before I was over 16 mpg in the city and 24 mpg on hwy.

I getting better in my 2012 silverado and driving hasnt changed.

 

GM hasn't gotten that damn thing lined out yet? What is the status!

[CAtaylor]

I actually have no complaint's with my mileage. I was expecting to get around 11-12 with the lift and tires. This is the best mileage I have ever gotten with a lifted truck and oversized tires.

[Mike1220]

My truck is leveled with an AFE air intake W/ K&N filter and a magnaflow exhaust, I was expecting a bit lower mileage but I am still getting about 14.5 MPGs on my last tank, and 13.4 overall life of truck. Only got about 800 miles on it and the MPGs have gone up a bit from when I first picked it up, however, so has the temperature, which I feel that is playing a large role.

[Ton J]

 

GM hasn't gotten that damn thing lined out yet? What is the status!

They had me take it to another Dealer to check it out. They reprogramed it again they said there is a problem with the Active Fuel Management System the manager has one and he said his MPG has went down as well and customer are starting to come in and complaining. But I looked my truck up by VIN there was program issue before it left factory. This will make the 3rd time for reprogram now be understand if they have any problems when reprograming it can damage the ECM.