jediknight120

My GXP is getting about 19 average right now, about 75% freeway driving.

RickAKATed10

iTrader: (1)

Last time I checked the DIC I was around 12. Yay me!

toxshox

iTrader: (3)

is there anyway to get some better mpg out of these ls4's i have a gxp 06 and the wife drives it mostly and it usualy displays 18's for avg mpg and that's alot of hyw driving mostly took it on a trip and the wind helped me achive 27.4 on the way home the wind wasn't so kind. is there a way to keep the dod enabled longer or allow it to engage sooner or something. I was thinking about doing a cold air kit and a magnaflow system not sure if that will help at all probably should check the plugs and o2's just haven't had time yet

Model16

With 4 cylinder mode my overally average was 18.7..

With it off its 17.9.....The drop is definitely worth it.

There is no way to enable DOD to stay on longer...Well I think you can change when it enables but you would need a Tuner to do so..The stock setting already enables it for when 4 cylinder would be more efficient...I think the only way you could get more is if you put on the Diablosport DOD tune...Ive never used it so I cant speak for it however..

STINGgxp

Hey guys,
I have read all the stuff about bad MPG but I have a 2007 GXP and I'm getting 25 when I drive easy and 23 N-change when I'm giving it the throttle hard(AVG numbers). When I check my odometer to fuel I put in the math is almost dead nuts. I no mods just a K&N panel in the air box (that's not a mod to me). I live in MI so I have good air but what gives with these other cars???

EmersonHart13

iTrader: (3)

Too many variables... What day of the week it was built on, what oil you use, maintenance records, driving style, weight, tire inflation, red lights, road conditions, weather, etc...

No way to directly compare mileage... And the EPA estimates suck so they are barely a basis for comparison. I think the only consensus that we might even be remotely close to coming to is... "If you are worried about MPGs do not buy a V8."

John

06MonteSS

yep, can be done with a custom tune for a diablo predator or trinity....

I can tell it to stay on longer, when it's allowed to come on, etc etc...

nighthand

If I don't drive like an idiot (which admittedly is a rare occurance), I get between 25-28 on the highway. Normally, I am around 14 locally (I won't say city, but....)

Brangeta

I made a topic awhile back about getting bad fuel mileage. I was averaging 12.6 to 14.8. I changed my driving style very simply and have been getting 16.0 to 17.2 ever since.

In 30 to 40 mph zones, accelerate moderately in 1st to ~15, 2nd to ~25, and stay in 3rd unless you're going faster than 40 to 45 mph. Once in 3rd you can accelerate slowly and the DOD or AFM will come on and put the car in 4 cylinder mode.

I was using 4th assuming that if the car would go into overdrive, I'd be better off. Well, I wasn't. I was burning more fuel to maintain 35 mph in 4th than I was in 3rd. So don't use 4th unless you're going highway speeds.

GXP303

I own a 2008 gp gxp. I used to get about 320 miles per tank. I am lucky to get 180 now. I have replaced everything conceivable to gain the previous mpg's and have had no success. New plugs and wires, new o2 sensors, new maf sensor and reverted to stock air filter box. Nothing has made any bit of difference. I am thinking that i may need to get the timing adjusted. I am at my wits end here. Any help would be appreciated. 11.8 mpg is just haunting my wallet. From 320 miles to 180 per tank is just not normal. What is the most perplexing of it all is that there are no codes being thrown at all. I watched the mpgs go down progressively over the past 6 months. Shall i just overhaul the motor or what?? I drive it extremely hard. Maybe it's just had it. Time for a new motor is all i can think at this point.

LS1 Racing

iTrader: (15)

How many miles on the car? Are you seeing any oil consumption? Driving habits change?

Timing doesn't "go out" on a modern motor, as it is computer controlled, so you can eliminate that. If your timing chain was badly stretched, you'd be throwing cam and/or crank position sensor codes, so I don't think it's that.

We need a bit more info to help with a diagnosis, though.

GXP303

my driving habits are the same as when i first bought it. Aggressive! It burns about a quart of oil between changes. I always buy an extra one each time around and add as needed. I had to replace my knock sensor wire harness recently. I have even tried using the lowest grade of gas available to see if it would help. I lost more mpg. What else can i replace on this thing to gain those mpg's back? Gas pump? My magnaflow cat back exhaust is tac welded only, but it was giving me optimum mpg (320 per tank) for 2 years. No one has an answer. Everyone in town is just as confused as me about this.

GXP303

52000k

Bob@BruteSpeed

iTrader: (16)

Your cats may be clogged. Bob

PurpleHaze9414

I just did plugs n wires got a new tcm ecm from overkill with a special 89 octane tune n put in new 02 sensor in post cat. Car isn't burning oil and I just went 450 miles on a whole tank... mainly highway driving

heavyft

Gas theft? Clogged/dirty throttle body screen? Cats overheating causing more fuel squirt to cool them. Higher ethanol blended fuel?

GXP303

It's worse now. My information center says that I am getting 8.7 mpg or 150 miles per tank. I am just going to bite the bullet and take her in to the dealer and leave all my limbs as payment. Just as long as she's back to where she should be. Thank you for your replies and suggestions.

Brangeta

Let us know what it ends up being!

MarineBri68

I am a new owner of an '06 GXP which has right at about 30k miles on it. I expected to get at least about 20MPG or was hoping for a little better if possible. Most of my driving is highway and I'll admit that when I first got the car I had my foot in it more than usual. (LOVE the sound of that V8 lol) However since then I have tried to not drive quite so aggressively and I'm STILL getting right around 16MPG.

I was reading that these motors came with DoD as an "option" but have no way to know if mine has it or if they all did actually come with it. Any ideas on what I might check to see what could be causing this crappy mileage would be great.

Little info on the car, It was garage kept without a scratch on it and had 28k miles on it when I bought it. When I first got it I ran some injector cleaner thru it and have tried running it with both 87 and 93 octane fuel with the same results. I haven't had the chance to check the air filter yet but I don't know how much difference it might make.....plus it's not like it's got 80k miles on it anyway.

Thanks in advance for any help on this.

Bob@BruteSpeed

iTrader: (16)

I'd replace the front 02 sensor and see if that helps out the fuel mileage. Bob