Ever since purchasing my 07 MC SS i have been getting awful gas mileage. Whenever my foot is on the pedal (8 Cylinder Mode), the instant economy reads somewhere between 3-7 MPG, and after driving it for 200 Miles, I averaged 11.2 MPG. Any ideas what may be wrong?

 

It's winter, I dont' know your driving habits, I don't know the driving conditions, etc.

You could have dirty sensors, o2 sensors, plugs, etc.

 

At first i thought it may be my driving habits, but im leaning towards something being wrong because i can have my foot on the gas not even far enough to accelerate (as long as it says im in 8 cylinder mode) and the instant economy reading will be around 5 MPG

 

When you accelerate with the LS4 you will always be in V8 mode. your tranny will shift you out after you get moving and not accelerating the car will move down to V4 and get better MPG.

 

But is it normal to be averaging 5 MPG in V8 Mode? seems quite low to me =/

 

That seems a lot low 5mpg is horrible

 

Your supposed to be getting close to 18mpg city. Tire air pressure good? Air filter good? Injector cleaner used reguarly. Do you have oversized wheels? When was the last time plugs were changed? Fuel filter change? PCV valve changed lately? Have you taken the bowling ***** out of your trunk? Anyway these small things will add up........


Ten Easy Ways to Conserve Energy | Efficiency & Conservation | Chevron

 

I have a HEAVYYYYYYYYY and I mean heavy right foot, and I'm averaging 18 mpg. So something has to be wrong

 

Wow, its almost like you know me... LOL, yes there are 6 bowling ***** in my trunk but i dont see how that would effect fuel mileage too much, that should even equate the weight of a passenger, right? and everything has been replaced very recently, My Monte only has 3900 Miles on it

 

Are you talking about the "instant" economy? Just asking because the instant economy screen is the one that shows the active number of cylinders. It is not an average reading or the car's overall mpg average. The next screen, average economy, shows that. If you are accelerating, the "instant" economy will be low. Same thing if you take your foot off the pedal, the instant will go crazy high. Still, the average you are saying is way low.

When you say 11.2 mpg is that what the car is calculating through the information center? Have you tried calculating the mpg yourself when you fill the car with gas to see if it's the same?

I'm averaging about 18 mpg with mine right now.