Ok, I'm at a crossroads. The manual says regular unleaded (87) or higher. However, most all of GM's press releases/engine documents say the for the 2.4 LE5 Ecotec that premium is recommended but not required. Recommended for what? What's the catch? I had to run premium in my old RSX, but that's because it had 11:1 compression. What do you guys run in your 2.4 Bu and why?

I run 87 cuz gas is expensive and the manual says 87 or higher. I have only run 2 tanks through it but it seems to run fine to me. I have read that with all the sensors telling the computer whats up a modern car will adjust and run fine on whatever I put in it.

I ran Super (93 octane) a couple of times. It smoothed out my 2.4 even more (if you can imagine that!), but my gas mileage actually got worse! I don't know if I was in the upper RPM range more because of the smoothness or what. So, I will probably only use super when I go on long road trips.

Conclusion....87 is perfectly ok!

All I have used is 87 so far and it seems to be doing great!

I run 87 octane in my car but ill put in some gas additives every other fill up just to try and add a little something extra from time to time..

What MPG would I expect if I do 20% city/80% highway driving and I don't have a lead foot?

Is there really a 4 MPG difference between the 4 and 6 cylinder engines? (30 hwy vs 26 hwy)

What MPG would I expect if I do 20% city/80% highway driving and I don't have a lead foot?

Driven conserviatively, probably 27 MPG +/- 1

Recommended 87 so why anything else?

Who can afford super?

Driven conserviatively, probably 27 MPG +/- 1

Interesting. I can get that in my Grand Prix 3.8L, unless I do a lot of around town driving. I wonder if it has something to do with the gearing and I wonder if the 6-speed will increase MPG at all.

Now that it's warmer, I'm starting to see 30+ pretty consistently with my 3.6. As I've said in other posts here, my worst tanks so far were still better than 25mpg, and those were probably about equivalent to 60/40 highway/city driving. I'd be seriously surprised to see the 2.4l get less than 29 or 30 in 80/20, and would expect 34-36 in the 95+ percent highway driving I do for work. One of the local dealerships has a black 2.4l LT with a sign in the window claiming 36 mpg (uh, I don't think it's an 09 with the six speed auto either). Maybe a shade optimistic for downtown Asheville, NC, but probably doable for highway trips.

Now that it's warmer, I'm starting to see 30+ pretty consistently with my 3.6. As I've said in other posts here, my worst tanks so far were still better than 25mpg, and those were probably about equivalent to 60/40 highway/city driving. I'd be seriously surprised to see the 2.4l get less than 29 or 30 in 80/20, and would expect 34-36 in the 95+ percent highway driving I do for work. One of the local dealerships has a black 2.4l LT with a sign in the window claiming 36 mpg (uh, I don't think it's an 09 with the six speed auto either). Maybe a shade optimistic for downtown Asheville, NC, but probably doable for highway trips.

that's great news!

I'm taking my first long trip in my 2LT this weekend, I'll do a fill up with regular one way and see what the MPGs are and then if I have any money left over from the casino do the higher grade fuel on the way back and see what the MPGs are....

I'm taking my first long trip in my 2LT this weekend, I'll do a fill up with regular one way and see what the MPGs are and then if I have any money left over from the casino do the higher grade fuel on the way back and see what the MPGs are....

Two tanks of gas may not give you a good indicator. A difference in wind alone can vary your mileage.

I run Shell 87 octane in our 2.4L Malibu. The only reason to use a higher octane rating is if you are experiencing detonation.