[5.0 Junkie]

I have put about 6800 miles on the car. Got it March 31 and left the next day and drove from KC to Louisville and back. I got 44.2 mpg calculated on the way back. Fuel added and what the DIC said used were within .1 gallons and indicated mpg was within 1mpg. Close enough for me. This level of accuracy continued for 6-8 tanks until one trip DIC was showing 45 or so and calculated was 38. Fuel put in tank was .6-.7 gallons above what DIC said was used. This has continued since then.

Today was 44.5 showing and 38.6 calculated. Car seems weaker and surges when under load and accelerating.

I'm still over 40 lifetime, but if DIC was accurate, lifetime would be over 43mpg.

I'm drive the car very easy and rarely go over 2000 rpm as I try to save gas as much as possible. I think I may pull the battery cable and see if the adaptives will reset and accuracy and mileage returns. I'd think I'd get better mpg now that it has 6800 miles on it, but it seems to slowly be going down.

Any input on this? Car is a serious dog off of the line even in first gear. Much worse than when it was new. I'm still happy with the car, but the mileage in the 30s for a trip that is 100% highway isn't what I'm looking for.

 

[Vetterin]

I can't explain your gas mileage but your car should rock in 1st, 2nd and 3rd!

 

[5.0 Junkie]

Negative on rocking. Like driving a 2 stroke. If you let the clutch out slowly and then try to go across traffic, you will get killed. I have had to clutch it to get the rpm up to actually accelerate to not get hit. It was adequate when new, but slow as **** now.

I have extensive aftermarket, racing, and automotive technology background. Anyone telling me how to drive will get kicked in the nutz.

I can't explain your gas mileage but your car should rock in 1st, 2nd and 3rd!

 

[wilson502]

i must say when i test drove one recently, the power seemed fine to me, and im a noobie when it comes to driving a stick!

 

[cruzeman]

on my last tank the dic told me i was around 43 but the real deal was only 38.something.

 

[oolowrideoo]

I'm seeing similar things in me Eco MT. Still in the 40's, but less that what the DIC says... Maybe someone is siphoning :-/

 

[70x7]

Maybe you have a boost leak somewhere
I would check your clamps along your turbo piping and tighten them if need be.

 

[Quazar]

Take it to the dealership. Sounds like something is wrong with it.

 

[eljackso]

Having a lot of the same issues, so I took it into the dealer this past week and they couldnt find any problems (no surprise)... I've been a car fanatic since the early 80s (do my own mechanical work and mods) and there is no doubt in my mind that my ECO is having some issues. Here's what I have, 5700 miles:

1. Fuel mileage going down, averaging 35-36 now (6MT)
2. Occasional lack of power when pulling out, feels like the brakes are locked in a way - I also have to clutch the tranny and rev to get out of peoples way
3. RPMs drop way off when getting off interstate, to the point that the car feels like it is going to stall (drops to 500 rpm)
4. Hesitation/surges at constant throttle with AC off - this one irritates the crap out of me and happens anywhere from 2100 RPM to 3000 RPM very randomly. The worst thing is that I will get on the throttle, realize there is no power and let off, then get right back into the throttle and it responds fine.

Not sure what is causing this, but I'm going to give GM a couple more chances to find/fix before I get rid of this thing. I truly am worried about long-term reliability at this point...

 

[5.0 Junkie]

Mine has stalled multiple times. Weird to give it gas at lower rpm, figure out you aren't going an faster and look down at the tach on 0. They have something goofy in the tune on these. I'm starting to think an aftermarket tune may be the key, but shouldn't have to mess with that. I'm sure the dealer will say everything is fine.

 

[eljackso]

I've been thinking of the trifecta thing myself, because I think the issue is related to fuel pressure and timing management by the ECM; however, I know that will void the warranty and when I look at the blue book on the ECO right now, I can actually come out ahead by trading it in. I do like a lot of things about the car or I wouldnt have picked it above the Elantra and Focus, but I refuse to accept "no problem found" for an answer - I am just hoping GM will figure out what the issue is and get it fixed.

 

[Gritts]

These issues sure sound like a failed/failing turbo--or something that is an integral part of the turbocharger system.

 

[csmock132]

Add mine to list. I also have an 2011 eco mt. Its even black also. Does the same thing. Surges under accel, Dies, bogs in first, second and third. Dealer says there is nothing wrong with it. I'm averaging 34 mpg. The surging drive me crazy.

 

[InsaneSpeed]

There was a update to the fuel mapping from GM about a month ago, make sure it us up to date with the dealer.
Later,
Steve

 

[oolowrideoo]

There was a update to the fuel mapping from GM about a month ago, make sure it us up to date with the dealer.
Later,
Steve

Was there a TSB for this? Do you have the number?

 

[limited360]

Add my ECO to the list... fuel economy is tanking and also having lack of power issues from time to time.

 

[5.0 Junkie]

I checked alldata. The only TSB showing was for the 1.8l and low power. There may not be a TSB out yet for a revised calibration. If there is one, I need to try it.

 

[eljackso]

Hopefully GM will step up and figure out what is going on; averaging 33.6 mpg this week and that's with 80+ miles of daily interstate driving with the cruise dead on the speed limit and 7 miles of city driving at 35-45 mph.

This sucks...

 

[5.0 Junkie]

Dealer didn't find anything like I figured. It has been 100+ here for weeks. Car is a dog. There is a thread in the engine forum that talks about GM saying it really retards timing with 87 octane. I filled with 91 this time and will see if it helps any.

 

[Quazar]

Hopefully GM will step up and figure out what is going on; averaging 33.6 mpg this week and that's with 80+ miles of daily interstate driving with the cruise dead on the speed limit and 7 miles of city driving at 35-45 mph.

This sucks...

Last week I dropped down to 34 mpg for one tank. It sucked, but it had to do mainly with running the air on full and having extra people in the car. The only advice I can give is what I have noticed.


- Slower accelerations. I lose most of my MPG on accelerations. You really notice it when you’re getting 44 DIC (city) and you take off from a light to get in front of someone and 1/2 a mile down you are sitting at 42.8. Think about it, having 100 miles on the tank that gave you an average of 44 and losing over a MPG after just one acceleration. It isn't even the RPM, you have RPM up too 2500 - 2600 and still get good gas mileage if your acceleration is slow.
- A/C is the biggest killer, mainly on 3 and 4. I run mine always at 2 with interior circulation on. I usually cool the car off with the windows down first and then switch on the A/C.

This tank I am back up to 44. Its been cooler and I have been taking it easy on the petal.

Its summer, I swear people are crazier and that forces us to be crazier. Heat makes people frustrated and because of that prob makes us drive crazier. That little bit of craziness makes a huge difference, especially with the A/C on.