Thread: Terrible MPG

Did you change the oil yourself? or do u got a sticker reminder?

Well I'm not sure about the older models. The 08 will shut down cylinders, up to 4, when posible. I just checked my MPG after my last fill up, and am getting Approx 24MPG. But I live in a small town and most of my driving is on state roads or interstate. And I'm sure when I'm putting my foot into it and the little display says my instant MPG is 1.7, that I am no where near 24MPG on that tank. I am the first owner of this car and know that it has never missed an oil change or a check-up.

But man if I got 10 MPG I wouldnt give up my GXP for nothing! I have never owned anything that had the performance and the handling all in one package. I have no plans to ever get rid of this car!

All years of the LS4 have DOD/AFM the cylinder shutdown. And i drive alot and all highway drving gets almost 10mpg better than all city driving. My best full tank MPG is 26. I did a half tank drive and got 30mpg.

Originally Posted by Panther427

All years of the LS4 have DOD/AFM the cylinder shutdown. And i drive alot and all highway drving gets almost 10mpg better than all city driving. My best full tank MPG is 26. I did a half tank drive and got 30mpg.

Thats great! I see those numbers on the "instant milage" display. I'm not sure how much I trust that display though.

Personally I have found that if i reset the Avg. Milage every time i fuel up the car, that it seems to be with in .5MPG of what i get when i do the math.

Originally Posted by Panther427

Personally I have found that if i reset the Avg. Milage every time i fuel up the car, that it seems to be with in .5MPG of what i get when i do the math.

VERY COOL! I just did that test myself and it was within .3. Close enough that I think I'll just check the readout from now on.

I've seen lower fuel milage this winter. Im working nights and get back to the yard i work out of around 5-6 in the morning. As i pull in with the work truck i hit the remote start. And hit it again before i leave so that the frost is all off the car. My new job is only about 4 miles from my house and with the cold weather im only seeing like14-16mpg. But im still seeing high teens low 20's mixed and mid 20's on long drives

yea seems a little low, my gxp i start up in the mornin for 5 min and drive 20 mi back roads and get about 16 mpg

i drive about 14 miles one way to work and iam pretty an agressive driver, my DIC shows 15.9 but if i hit cruise control it jumps to 32. fule managment system kicks in on cruise control right off the bat according to GM dealership... but i love my car and just my out look if your wanting gas mileage get a honda, you want a bad ass ride stop *****en

old thread is old

i thinking about putting different oil in mine, then what my dealer put in there. right i get 14.5

I'm averaging about 26 mpg. My commute is 120 miles round trip with mostly interstate driving (around 80 mph). I am definitely not complaining on a 5.3L v8. Should this be higher?

Originally Posted by nicksilvergt99

Wow. I get 16.6 driving like a complete maniac, usually I get 18-26

I love when the V6 guys chime in on the wrong thread.

I love how old this thread is and how you V8 guys keep bringing it back.

Originally Posted by nFavor

they said they needed to replace the fuel pressure relay

relay or regulator?

I have had my GXP since April this year. drive 80miles around trip everyday, only 2 miles off I-20. Avg 22-23mpg. My only thing is straight long trip mileage (360miles) our best was 24.5mpg. Guess that is not too bad. I Love my car.

Update for my GXP.. See above. I bought the K&N air intake and the Magna Flow 16726 Cat-back system and my fuel mileage has climbed. doing 65mph I get about 30mpg, when I hit 75 it drops to 25mpg or so depending on the wind. =-)