Not-so-good Mileage.Please Help

[jblackburn]

Well,keep in mind,only the LS models have the 1.8,others have the 1.4 as well as different transmissions,like I said above,the ls I have is a 6t40 which ALL 2012 LS's have,while the 2013,has a 6t30 Tranny,and will have either one of those in the 13 LS.

But also when I put it into manual,it displays that it shifts into 6th when I upshift,and thats when it says 3000rpms@70mph.



Thats understandable,but i'm at 3000@70mph.Thats not right,5 speeds usually shift at 3000@70mph,not 6 speeds.Hopefully they can agree with my hypothesis,it makes perfect sense,and I wouldnt have a single clue why else it could be.Guess I'll find out in the morning.

Bump your transmission over to manual mode, as several posters here asked about. Monitor the RPM, and see if there is a difference between 5th and 6th gears in RPM @ highway speeds.

Traditionally, small motors run more revs on the highway because of their powerbands. My friends 2004 Civic is screaming at 4000 RPM at 80. 1.7 liter motor; still gets 38+ mpg on the highway.

[ZachFools]

I'm not necessarily understanding what you mean by seeing a difference in 5th and 6th?I mean like regardless of when I shift into 6th it will be around 3000rpms still?

[jblackburn]

I'm not necessarily understanding what you mean by seeing a difference in 5th and 6th?I mean like regardless of when I shift into 6th it will be around 3000rpms still?

The RPMs should go down when you change up to 6th gear from whatever they are in 5th (3500 or more, maybe?)

If it does change up gears and settles at 3000 RPM, that's just the way that your transmission is geared. Nothing you can do to change it. Mine's a manual, so I really don't know what the automatics settle at. I drove 2 automatic Cruzes and hated them both.

[spacedout]

3000RPM seems really high for 70MPH, if it is in 6th gear it almost sounds like your torque convert is not locking up. My 2012 1LT runs 2,000RPM at 58mph. Think at 72mph I am running 2600RPM but would have to verify.

[ZachFools]

The RPMs should go down when you change up to 6th gear from whatever they are in 5th (3500 or more, maybe?)

If it does change up gears and settles at 3000 RPM, that's just the way that your transmission is geared. Nothing you can do to change it. Mine's a manual, so I really don't know what the automatics settle at. I drove 2 automatic Cruzes and hated them both.

Theres no way someone would gear a 6 speed at 3000rpms,that would eventually wear over time,5 speeds normally are at 3000rpms.

3000RPM seems really high for 70MPH, if it is in 6th gear it almost sounds like your torque convert is not locking up. My 2012 1LT runs 2,000RPM at 58mph. Think at 72mph I am running 2600RPM but would have to verify.

Thats almost exactly how the 2013 I drove earlier showed.And its a 1.8 LS.The more I think about it the more certain I am that its the tranny.

[sciphi]

Something's not right if it's spinning 3000 RPM at 70. Not even a 2011 Cruze spins that high at 70. IIRC at 70 I'm at 2300 RPM.

[ZachFools]

that sounds completely right.im aboutvto take it into service so they better figure something out

[epcotbob]

I checked my 2013 1.8L LS Auto this morning. At 70mph I'm at about 2500rpm, 60mph is like 2200rpm.

[spacedout]

It would be best if someone with a 2011-2012 LS automatic would reply to this thread to see if the RPM the OP is seeing is normal. Since there was a transmission change form 2012 to 2013 it very well might be.

[epcotbob]

Although I think you're on the right track something's still not right here. My 2012 ECO MT is at 2000 RPM at 65 MPH in 6th gear. I don't see how the 2013 LS is at 2000 RPM at the same speed. I do think your car's 3000+ RPM is an indication that your car is NOT shifting to 6th gear, however.

Are you saying that you would expect the RPM's to be a little higher on the 2013 1.8L Automatic? Just curious because mine spins at about 2300RPM at 65mph.....I was surprised to to see someone spinning only 2000RPM with exactly the same car.