# Gas mileage



## 1stGTO (Sep 19, 2004)

Hello All-

have to make this quick.. 

I have had my GTO for 2 weeks now. I am avg 12mi city and 16mi highway

I stay out of the throttle, trying to break the engine in nice and easy. 

6 speed, Red w/moonroof, running 93oct dealership is clueless, I knew more about the car then they did. 

Your Take?


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## blue goat (Aug 19, 2004)

Just took the family out for a nice Sunday dinner at a town 30 miles away. No stops. I live in wide open Texas country. With the cruise set at 72 it was showing 28 mpg. I get 20 or better @ 40 mph.in 4th in town. Somethings wrong man. You need to hook it up to a gizmo to let her tell you what's wrong.


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## catchmeifucan (Sep 12, 2004)

*Auto Mileage*

At 400 miles and with the automatic, my average so far is 15.5 MPG. Being a new toy, I have put my foot into it way too many times. 

It left the dealer with that average at 9 MPG. They must of rode her hard on those test drives.

I figure if I can average around 17 - 18 MPG after the engine breaks in, I will be happy as this is higher than my SUV used to get.


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## 1stGTO (Sep 19, 2004)

*Mileage*

Thanks Blue Goat. Were do I go, again the dealership is clueless, I'll try asking the mechanic there to check it out. I never would have purchased this vehicle knowing that this was the type of gas mileage. I know what it is rated for is off by a few miles but this is ridiculous

I love my ride though, man its nice.. My payments are 517mo for 5yrs Ouch!!!

Ill update you if I find out what’s going on.

Take care, and watch out for the smokies


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## JBarnes (Jul 28, 2004)

My first two tanks were running 21.3 MPG, I too drive mostly on open highways and back roads, minimal stop and go driving.


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## monaro (Jul 30, 2004)

1stGTO said:


> Hello All-
> 
> have to make this quick..
> 
> ...


 first i would wait until you have some more miles on it before you get to excited about mpg. i am sorry your talking to a guy whose commuter car is a F250 w V10 so 12 mpg sounds good to me. my gto is for week end and pleasure driving so i dont pay to much attn to milage.


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## George8211 (Sep 21, 2004)

Don't be too hasty to try and calc mile per gallon. For the first 500 hundred miles or so, your engine breaking in by wearing hard metal components to the soft ones. During this time you have extra friction and your compression will be lower during the break in.

Many of the new computers have different programs that handle fuel and engine management systems. These programs will run different sub routines the more miles you put on. I think at about 2,000 miles they run the full normal programs (maybe someone else has more info on this)... this is to keep you from hurting your own car.

Also when you are checking to see what the average MPG is, make sure you are resetting the ave. It is an average over all miles driven to include creeping forward at traffic lights.


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## GTOJOE (Sep 10, 2004)

My average has been, 1st two tanks were around 18mpg, last tank was 21.3
This tank is still near 24 mpg. As long as someone doesnt want to go for a test ride it should stay there  Dont forget to reset your avg mpg to 0 at each fillup. That will give you mpg for that tank. If not you will get a life time average.
Joe


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## Groucho (Sep 11, 2004)

Just finished my 500 mile break in period so I felt safe to take it really easy on the engine, just as an experiment. My 75-mile each way commute over the mountains to the high desert nets an average mpg of 19.1 mpg. I'm sure that will improve.

Oh well...I didn't buy it for its frugality!


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## GTO TOO (Sep 10, 2004)

1STGTO,
Something is wrong. ECMs learn very fast on new vehicles ( less than 50 to 75 miles depending on how you drive) Even though mileage should improve as an engine breaks in, yours is not running correctly if you are driving as you say. Where in the country do you live? Mountains or cold?? If you haven't set a check engine light, you might still have a sensor problem. Have the dealer, one that knows what they are doing, put a TECH II on it and look at the outputs from the sensors with the vehicle running. Does coolant and Intake air temp look like it should?? Those are the two most common that could cause it to run rich. ( or maybe never go closed loop) Also have them look at the TPS throttle position sensor both closed throttle and WOT. 
Ask the dealer..also when they have a TECH II hooked up ask if it's closed Loop...What do the O2 sensor read?? They will find something if you are really just driving normally at 12 to 16. In a 6 speed thats too low..

Here's another way we might help you on this board. AFter the engine is fully warm.Go drive 55 MPH on Flat level pavement. 1st in 5th gear at 55mpg, then 6Th gear at 55 MPH at both speeds with a speady throttle note the INST FUEL ECONOMY on that screen in the dash. Post it here. Others can drive their 6 speeds at the same speed and gear and quickly tell how far OFF your's is from normal MGP....Just a thought.

How about someone else checking thier INST MPG screen at 55 in 5th and 6th gear???and posting results.
I love a science project.....


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## Redline (Aug 10, 2004)

since when do GTOs have moonroofs?


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## George8211 (Sep 21, 2004)

GTO TOO said:


> 1STGTO,
> Have the dealer, one that knows what they are doing, put a TECH II on it and look at the outputs from the sensors with the vehicle running. Does coolant and Intake air temp look like it should?? Those are the two most common that could cause it to run rich. ( or maybe never go closed loop)


In his post he stated that he took it to the dealer... and they did not find anything. If any of what your decribing is happening, the GTO would have shot a number of codes out imediately... of course this is the first thing they would check.



> Also have them look at the TPS throttle position sensor both closed throttle and WOT. Ask the dealer..also when they have a TECH II hooked up ask if it's closed Loop...What do the O2 sensor read??


I don't claim to know every thing about these cars... but just a simple question for you... ask if *exactly what * is a closed loop??

Also, when he asks the dealer what the O2 sensors read... What would be the range that would show a problem or not show a problem?

Thanks for these answers... don't send a Ranger into battle with a gun, but not any bullets.. :cheers


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## lisatw151 (Sep 8, 2004)

I just got back from a fishing trip to southern Georgia. It was a seven hour drive, all highway. My avg speed was 72.4mph and gas mileage is reading as 25mpg on this last fill-up. Watching the instant MPG while I was driving, it stayed right around the mid 20's while cruising, rising and dropping depending on the terrain, passing other veh's (which i did a lot!!LOL) etc.... My GTO is my everyday car, my 16 mile one-way commute to work being a combination of hwy and city driving, and I'm averaging about 17mpg.


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## rock421 (Aug 7, 2004)

Yeah, I also reccommend storming in to your local dealer and telling them how to work on your car. :confused
Be cool with you dealer, talk to the service manager and explain your concern to him (her) AFTER you have given the car time to fully seat the rings. If you go in there acting like an idiot, how willing do you think they will be to help you? Granted some dealers are pretty bad, but if you develop a good relationship with the service dpt. early on, I just may benefit you in the future. Most dealers have in house authority to perform "good will" warranty repair up to 60k IF they like ya. The guys in our service dpt. seems to bend over backwards (and forwards sometimes  ) for good customers.
Just my opinion....B


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## Redline (Aug 10, 2004)

:agree 

There are three people you dont piss off in this world....

Waiters/chefs, caddies, and people that work on you car... all of these people can make your day go down hill really quick :shutme


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## George8211 (Sep 21, 2004)

:agree


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## GTO TOO (Sep 10, 2004)

First I did not say storm the dealership. Let's not twist what is said !!
1stGTO stated " dealership is clueless". I suggested several areas to look at and how to look at them. This site has been very calm but I sense some emotion in several of the newer posters. I would hope this site does not deteriorate to the level of most others. Rock you sound as if you work in a dealership. They work on cars they do not design and test them.
George, you are of the opinion that anything will set a code. Many things will, but some problems will NOT set a code. Sensors do not always just fail to one extereme or the other some can just output the wrong signal and cause issues. Again no offense but you are asking what closed loop is and yet have an opinion on how codes will set. I have some knowledge on how codes get set and how the system actully works. I was just trying to help. To answer your specific question on closed loop. That is one mode where feedback from the O2 sensors is used to maintain stoichometric Air/Fuel ratos. Stoich is where modern catylitic convertors have the best mutual efficencies for HC, CO, and NOX. While most engines run closed loop most of the time there are many operating conditions when an engine is NOT closed loop. ie. during warmup, and under some high load operating ranges. Watching both the front and rear O2 sensor outputs on a TECH II tool can help indicate what the problem might be. This engine seems to be running too rich for too long. If the dealership service is truely clueless they might be open to a few suggestions. That is all I tried to provide.


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## George8211 (Sep 21, 2004)

Well this time you DID provide (verus tried to). This answer is wwwaaayyy better than your first one. Thanks, I personally did not know how about the closed/loop durning warm up. It seems the computer is not really making so many adjustments until the engine is warmed up... at least in regeard to the O2 sensors. You mentionad the front and rear sensors, do you know where they are located on the GTO's exhaust system??

Is the GTO exhaust a duel exhaust with some kinda H pipe that connects to to balance the pressure... or is a single pipe with a single muffler that splits out to create 2 tail pipes??


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## rock421 (Aug 7, 2004)

OK, OK, so maybee "storming" was a little too dramatic. You understand what I mean though. It's just something I see happen from time to time here at the dealership. Some techs get real pissy when they think they are being questioned or challenged. These guys can be sort of sensitive that way.
I guess my hidden messsage in all of this is that you can catch more flys with honey.


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## muohio (Sep 22, 2004)

George8211 said:


> You mentionad the front and rear sensors, do you know where they are located on the GTO's exhaust system??
> 
> Is the GTO exhaust a duel exhaust with some kinda H pipe that connects to to balance the pressure... or is a single pipe with a single muffler that splits out to create 2 tail pipes??


When I looked under the car last night, I appears that the first cats are just inside the front tires along the firewall. The first O2 sensor is located just in front of them and then the second is under the middle of the car past the second cats. The car has an H pipe that from what I understand is blocked off for the GTO but not the Holden.


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## BRIAN P. EWING (Aug 7, 2004)

*Bolt Pattern?*

Does Anybody Know What The Bolt Pattern Is On The 04 Gto's? I'm Thinking About Getting A Set Of Wheels And I've Been Told By A Wheel Manafacturer It's 5x115m, And Then Someone On This Site Said It's 5x120mm. I Know This Has Nothing To Due With The Ongoing Topic, But It Sounds As If You Guys Know What Your Talking About.


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## rock421 (Aug 7, 2004)

I think I may have read the same 120mm as you did. None of the factory info lists the bolt circle. Someone here will know for sure.

Brian


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## George8211 (Sep 21, 2004)

BRIAN P. EWING said:


> Does Anybody Know What The Bolt Pattern Is On The 04 Gto's? I'm Thinking About Getting A Set Of Wheels And I've Been Told By A Wheel Manafacturer It's 5x115m, And Then Someone On This Site Said It's 5x120mm.


I don't know the answer to your question. You might check with these guys... when you get the answer please let us all know... Thanks 

http://www.tirerack.com/index.jsp



> I Know This Has Nothing To Due With The Ongoing Topic


In the future you should start a 'New Thread' on the main page. Then people that see your title and are knowledgable in that area will check it out and have a wheel conversation. When you get the answer, maybe you can post it on the new thread... :cheers


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## George8211 (Sep 21, 2004)

So it sounds like the O2 Sensors and exhaust set up are about the same of the Corvette.


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## rock421 (Aug 7, 2004)

Well done George!!!!!!!!!!


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## GTOJOE (Sep 10, 2004)

It's getting better. Just changed the oil over to 5w30 Mobile1 last weekend.
Today i ran down to Detroit and averaged 28.7 MPG.  Not Bad for a V8
Joe


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## George8211 (Sep 21, 2004)

rock421 said:


> Well done George!!!!!!!!!!



Thanks Rock... If there is anyone here that has Never seen an exhaust system off the car.... 1,000 words could never do it :cheers

And... Now this opens the door for discussions about High Flow cats ... and X pipes and headers  

I see Larry being apart of that discussion.


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## LarryM (Aug 17, 2004)

George8211 said:


> ....And... Now this opens the door for discussions about High Flow cats ... and X pipes and headers
> 
> I see Larry being apart of that discussion.


George - What? Are you trying to get my wife to skin me alive too???? I thought we were friends!??!!!  

I dunno about this... I *love* the way the car sounds right off the show room floor. Not that I've had that large a sampling, but easily the best stock exhaust I've ever heard. While I did see the crimps in the stock exhaust, and recognize the improved flow characteristics of headers... I just don't think I'm ready to start ripping up my car like that.

---Larry


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## rock421 (Aug 7, 2004)

Larry needs to save up for two new (rear) tires anyhow. Huh Larry.


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## LarryM (Aug 17, 2004)

rock421 said:


> Larry needs to save up for two new (rear) tires anyhow. Huh Larry.


You been peeking in my mind haven't you Brian?

The dealer where I got my car from has a Yellow GTO that they put some fancy chrome wheels on. They, obviously, can't sell the wheels they took off till they sell the car with the chrome ones, but I did mention to my sales guy to keep me in mind when/if they do.

Hey Grocho - your car has different wheels/tires, what did the dealer tack onto the car for those? My sales guy says the ones they put on are --$4,000-- OUCH! He doesn't think they have a prayer in hell to sell those. That's a pretty significant bump in the price tag. 

---Larry


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## Groucho (Sep 11, 2004)

LarryM said:


> Hey Grocho - your car has different wheels/tires, what did the dealer tack onto the car for those? My sales guy says the ones they put on are --$4,000-- OUCH! He doesn't think they have a prayer in hell to sell those. That's a pretty significant bump in the price tag.


I think your dealer is pulling your leg. I paid $2350 extra for the wheel/tire/necessary bodywork upgrade (including the window tinting)-- $200 over the dealer's cost.

If you go online you can find 18" Momo Tuners for ~$400/ea and Tire Rack has the tires for $135/ea. There were also spacers and the body work involved so I got off pretty good. It helps that my salesguy is a tuner gearhead-- He had actually built my car up for himself but then couldn't follow through with the purchase...


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## LarryM (Aug 17, 2004)

Ya I dunno. The sales guy himself is a pretty cool guy, and I want "the left overs", so I don't see any reason for him to jerk me around on the price of the fancy wheels. He doesn't think they will ever sell the car with $4000 wheels on it.

Now, it could well be that the dealership has decieded that they want to be greedy on these and have marked up the price to be retail PLUS profit. I personally thought they were butt-ugly and wouldn't pay $0.02 for them... but then again, I'm probably in the minority when I say that I think the stock wheels look great.

So maybe somebody will like them, but not $4000 worth.

---Larry


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## GlennH (Sep 22, 2004)

I've only got 400 miles on my GTO. I averaged 13.8 MPG on the first tank and I'm sitting right at 13.8 half way through my second tank. They delivered the car to me with a full tank of gas and the salesman admitted to me, when I went back in a few days after delivery, that he filled it with regular  I can definitely tell the difference in performance with the 91 octane I filled up with but need to find an Amoco station with 93 for the next tank. I'm sure I'm putting my foot in to the car way too much for the number of miles I have. I worked in finance for several car dealers back in the late 70's and early 80's and always drove new demos. The harder I broke them in, the faster they ran. However, I never put more than 6,000 miles on a car so I didn't have to suffer the cost of whatever damage I may have caused. It's probably too late now, but am I really screwing something up by running it hard? I did call Granatelli the other day and inquired about their Predator programmer. They said I should wait until I have 2,000 miles on it before reprogramming so George8211 probably knows what he's talking about when he said the computer doesn't run the full normal programs until that mileage. George also said that that was to prevent you from hurting your car, so, does that mean I'm not hurting it by running it too hard?


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## 1stGTO (Sep 19, 2004)

*Follow Up on MPG*

Ok, I admit that I drive my GTO a little aggressive then I should. SO I decided to Granny Drive it for a few days as I commute over 45 mi 1 way to work. so at the very best running 72mph im avg 18.1, now that's not what the sticker said. 

At $ 2.25 a gallon, I may have made an mistake. 

Now the good part, nobody wants to race me. I have owned all types of muscle cars, the 70's were good to us. owned a 2001 z28 LS1 w/Borla Exhaust, hyper tech chip programmed and was not as fast as my GTO. It was faster going over 150mph, the GTO stops handling well at 128mph. The fastest car I have ever owned was a firebird, Borla/Eldebrook heads 3" cold air intake, that car would have set the pole at any Nascar track : )

LARRY-
I have notice the exhaust getting a little quieter too! what is up with that? 

--Mark


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## George8211 (Sep 21, 2004)

Hey Mark... About your exhaust getting quieter. Well, your just getting used to it. Generally they get a little louder over the first couple thousand miles. My GHL sounds perfect at 10,000 miles.


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## 1stGTO (Sep 19, 2004)

*Exhaust*

I sure do hop that the exhaust does get a little bit more on the hot rod sound of things. I am at 1700mi right now, picked it up about a month ago with 229mi. 
I think the newness start to wear off when you have to pay for it every month, the next 5 yrs I hope that i dont have any problems out of it. by then Hopefully my son will be almost ready for it, if gad isnt at 4.50 per gallon by then : )

I am already to MOD this thing, anyone making aftermarket or performance parts yet? :cheers :cheers 

btw.. the coolest part of driving my GTO is, when I am on the hoghway, ( always ) and cruising at 89mph and you slam it up to 5th jump up to 100mpgh AND TAKE IT HOME IN 6TH.


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## GlennH (Sep 22, 2004)

There are several places I've found that have performance parts for the GTO; slponline.com, lmperformance.com and pfyc.com. Several of the items are pre-released but won't be out until mid October, namely the Borla cat-back and the K&N air charger (ther two things I want). I did order the Granatelli Predator the other day and it just came in this afternoon. I'm really eager to reprogram tonight and see if I can tell the difference. I only have 550 miles on my car but a guy here at work who races his corvette didn't think I was hurting my car to break it in a little hard. I've tried the last couple of days to be a little kind and even took it out Sunday and put 100 freeway miles on it at 60-80MPH. I'm psychotic with it though, I just can't keep my foot out of the accelerator.


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## LarryM (Aug 17, 2004)

1stGTO said:


> ...LARRY-
> I have notice the exhaust getting a little quieter too! what is up with that?
> 
> --Mark


Mark - I've chalked it up to a couple things, mostly wax in my ears (ew!) - and in the stop-n-crawl traffic I wasn't able to do anything but the mildest starts.

Now I've taken to letting the car in front of me get a 2 or 3 car head start -and then- taking off. That way I get a little bit of fun.

Plus, the weather here has been beautiful lately, no need to have the windows rolled up with the air on, so its cruisin with the stereo (tailpipes) blasting.

Man, I love this car!


---Larry


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## HOT GOAT (Oct 5, 2004)

*Gas Mileage*

Hello All,
While reading through the various comments on mileage, I see very few A4 results. I would like to hear from more A4 owners and also know if you are checking mileage with or without airconditioning on? I would prefer an Auto at my age, but if it is a great deal of difference I will fight the wife for the M6. As to gas mileage not meaning anything, at $2 a gallon it is a definite consideration for me.
HOT GOAT :confused


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## Whiteshadow (Sep 28, 2004)

I guess I'm lucky then that I live in Iowa, where the most expensive gas is still around $1.80. 

For those of you who have been wondering about aftermarket parts for the car, yes they are available you just need to research. 

I found a few aftermarket exhaust systems soo far. Corsa makes one (check out the Corsa website, or Lingenfelter's site) Borla makes one (haven't checked the website, but their system is supposed to ship out in a week or two) SLP makes the loudmouth, a very affordable system, and supposedly they will have a quieter exhaust coming out shortly as well. I found this on ebay, for $539 or so. Not bad for full exhaust.

Lingenfelter and K&N make intake kits for the car, I'm sure there are others.

After that, just look at other places selling LS1 parts. For instance, the LSX manifold will fit on the GTO, as well as throttle bodies, Mass airflow sensors, heads, cams, all the fun stuff. It shouldn't be too hard to get some decent power out of the car.


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## SFLGOAT (Oct 7, 2004)

HOT GOAT said:


> Hello All,
> While reading through the various comments on mileage, I see very few A4 results. I would like to hear from more A4 owners and also know if you are checking mileage with or without airconditioning on? I would prefer an Auto at my age, but if it is a great deal of difference I will fight the wife for the M6. As to gas mileage not meaning anything, at $2 a gallon it is a definite consideration for me.
> HOT GOAT :confused



Picked up my silver/red A4 on week ago today. Avg on first tank of BP 93 was 13.2 with more than occasionally putting my foot in it. (it's like trying to eat one potato chip) Had 39 miles on it on delivery. I do mostly city driving to/from work about 10 miles each way with a/c cranking. It is still cookin' in south florida this time of year. (I will have the windows tinted next week). 

I went to the dealer looking at a G/P comp G, (my 3 yr old 2002 2dr GT rode better... what a dissapointment) With the GMS discount and all the incentives, the GTO was extremely affordable & after driving the GTO it was a no brainer. I LOVE THIS CAR!!!!!!! 

I went the auto route for the following reasons:

1. Been there, done the stick thing in SFL traffic for several years- your tire of it quickly I mainly do city type driving now. The mileage is about the same on either trans.

2. The wife REFUSES to drive a stick. (you have to keep the designated driver happy).

Unless you do a great deal of highway driving, you are not really saving much (if any) by going to the stick.

What I recently found annoying is the pedal kickback on the gas when you put your foot in it. At first I thought this will keep my MPG up, but I now instinctively turn off the traction control as soon as fire it up. Does anyone out there know how this is controlled? Does the computer retard timing or just restrict fuel. From a fuel consumption standpoint, I am wondering whether leaving the traction control on and having the computer take over is more detrimental than putting my foot in it and enjoying this car for what it is made for. 

If I want gas mileage, I'll drive my wife's Saturn.


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