Pontiac GTO Forum banner
1 - 20 of 65 Posts

·
Registered
Joined
·
210 Posts
Discussion Starter · #1 ·
went to the dealer today to see why my highway mpg is only 21 no matter how hard i try. he askes me what brand of gas that i use? i said that i usually use "cashions" down the street. he said to try BP and that my mpg would go up 3-4 mpg highway. i am pretty sceptical, but he swore by it. he worked for them for years and said the quality in brands is very different. i have always read they were all identical, but i will give it a try. 21 mpg going 70mph in 6th gear should equate to at least 25 or better.
 

·
Registered
Joined
·
67 Posts
That is odd. I have seen 24 mpg on freeway trips doing 80 and 2000 RPM and Traction Control on. This is pretty much standard for me and I use most Chevron and 76 Premium which in California is 91 Octane. My car is an '05 M6.

In City driving I see 17 - 19 MPG and I skip shift like from a red light I go from 1st to 3rd gear. From 2nd to 4 th gear and if I see enough room between red lights I might go on to 6th gear at 1100 - 1500 RPM.

However, every once in a while I stomp on it to get the "cobwebs" out of the system and all that moisture in the exhaust. Just to remind myself it is still a muscle car.

You should see more the MPG than 21 if you have been babying the car like you said.
 

·
Registered
Joined
·
210 Posts
Discussion Starter · #4 ·
exactly! i baby it to the extreme. skipping gears, etc. i'm annoyed. but, if the a/f mixture was wrong, wouldn't the cars computer trip a code? it must be pretty correct to have not thrown a code yet?
 

·
Registered
Joined
·
168 Posts
Fuel is different from one brand to another,check toptiergas.com.I use only Shell in all 3 of my cars.
 

·
Super Moderator
Joined
·
8,433 Posts
As I posted previously on how well my car gets great highway MPG.... I do not let the tank get below half, and I alternate premium 92 octane to middle grade 89 octane gas on fill ups. The gas I use is...... either from Wawa ( minute market ) or Bj's. (similar to Sam's Club). When I registered my 28.4 on a long haul I filled up with Amoco. When I got 27.6 on a long haul I was using Bj's fuel.

Wawa gas and Bj's gas is not prime fuel, but I am getting great mpg with them.

I would tend to think if you are only getting 21 mpg at best on highway, there may be something wrong. I'd insist on a tune up. I am getting 19-20 in a combination of town and highway driving. 17-18 in town driving.
 

·
Registered
Joined
·
569 Posts
GTO judge said:
As I posted previously on how well my car gets great highway MPG.... I do not let the tank get below half, and I alternate premium 92 octane to middle grade 89 octane gas on fill ups. The gas I use is...... either from Wawa ( minute market ) or Bj's. (similar to Sam's Club). When I registered my 28.4 on a long haul I filled up with Amoco. When I got 27.6 on a long haul I was using Bj's fuel.

Wawa gas and Bj's gas is not prime fuel, but I am getting great mpg with them.

I would tend to think if you are only getting 21 mpg at best on highway, there may be something wrong. I'd insist on a tune up. I am getting 19-20 in a combination of town and highway driving. 17-18 in town driving.

I think there is something wrong with your car (in a good way :))- you are getting better than advertised mileage- which even equaling is a feat in ANY car. I average 18.7 with every tank with a mix of highway, city and abusing it- and this is with the Procharger on. Got in the mid 19's before the blower. I can squeeze out 22-24 on longer highway trips depending on driving. I don't think there is anything wrong with anybodys GTO that is getting low 20's- sounds more like the rule than the exception from what I have heard from many owners. Hell, like others have said- 400 hp and 3800 lbs- can't expect too much :).
Joe
 

·
Super Moderator
Joined
·
8,433 Posts
kwiktsi said:
I think there is something wrong with your car (in a good way :))- you are getting better than advertised mileage- which even equaling is a feat in ANY car. I average 18.7 with every tank with a mix of highway, city and abusing it- and this is with the Procharger on. Got in the mid 19's before the blower. I can squeeze out 22-24 on longer highway trips depending on driving. I don't think there is anything wrong with anybodys GTO that is getting low 20's- sounds more like the rule than the exception from what I have heard from many owners. Hell, like others have said- 400 hp and 3800 lbs- can't expect too much :).
Joe
The MPG I posted is the BEST I have gotten. I don't go on long trips all the time. If I had to give an average for all my driving, I'd have to say its about 19-21 mpg. When I go on long trips that is when my mpg increases, but that is non stop. Others have reported getting in 25-28 mph as well. By no means is this all the time I am getting 28 mpg.

As I stated previous, our engines are not all created equal. Some are getting better performance than others, including oil usage.
 

·
Registered
Joined
·
738 Posts
GTO judge said:
The MPG I posted is the BEST I have gotten. I don't go on long trips all the time. If I had to give an average for all my driving, I'd have to say its about 19-21 mpg. When I go on long trips that is when my mpg increases, but that is non stop. Others have reported getting in 25-28 mph as well. By no means is this all the time I am getting 28 mpg.

As I stated previous, our engines are not all created equal. Some are getting better performance than others, including oil usage.

Ok I am getting sick of these post,You need to the follwing. Get a Tuneup check you spark plugs. Have youre ecu checked out to be sure the goat is not running rich. check you airfliter I had a friend who has an grand piix 75,000 miles chaned filter once changed it got 3 more mpg. And check your cooliant levels espicaly if you live somewhere hot, And youre oil!!
 

·
Registered
Joined
·
1,658 Posts
redrocketgto said:
Fuel is different from one brand to another,check toptiergas.com.I use only Shell in all 3 of my cars.
Redrocket is 100%correct. In fact, GM has a technical service bulliton for all their vehicles to use toptiergas recamended fuels only.:cool
 

·
Super Moderator
Joined
·
8,433 Posts
MJGTOWISH said:
Ok I am getting sick of these post,You need to the follwing. Get a Tuneup check you spark plugs. Have youre ecu checked out to be sure the goat is not running rich. check you airfliter I had a friend who has an grand piix 75,000 miles chaned filter once changed it got 3 more mpg. And check your cooliant levels espicaly if you live somewhere hot, And youre oil!!


If you're getting sick of the posts, you have a simple decision to make. Don't read em'.
 

·
Registered
Joined
·
275 Posts
enjracing said:
gto judge is spot on. get over yourself. this wasn't one of my MPG questions that annoys some of you. it was a gas question. if you don't like these kinds of topics, don't read them.
:agree

We're here to help one another as we all have something in common, a GTO. There aren't limitations to what someone should or should not know.:cheers
 

·
Registered
Joined
·
25 Posts
I think it does matter what brand of gas you use. I recently purchased a programmer ( which by the way woke up the car ) from superchips. As soon as I did install, I notice the differenced but also a lot of pinging under hard acceleration. I called them right away with the problem and they told me to use better gas, like from chevron. Sure enough this fixed the problem. So I think the brand of gas does matter, but this is just my 2 cents worth.
 

·
Registered
Joined
·
210 Posts
Discussion Starter · #18 ·
ok guys. we will all find out soon. i ran my tanj of crappy gas out almost to the vapors and put in 93 BP. we wil see what happens with me doing everything identically driving wise and using the exact same freeway route.
 

·
Registered
Joined
·
5 Posts
Better Mileage

One other thing that EVERYONE needs to know. Here on the west coast we have Arco gas. This gas as with other off brands has up to a 10% ethanol blend. This can be BAD on mileage. You will see a 5 to 10% drop in mileage using the ethanol blend fuel. To avoid this, use ONLY Chevron, Shell, Unocal. These providers use other fuel blend additives to meet emission standards.
 

·
Super Moderator
Joined
·
8,433 Posts
smyles said:
One other thing that EVERYONE needs to know. Here on the west coast we have Arco gas. This gas as with other off brands has up to a 10% ethanol blend. This can be BAD on mileage. You will see a 5 to 10% drop in mileage using the ethanol blend fuel. To avoid this, use ONLY Chevron, Shell, Unocal. These providers use other fuel blend additives to meet emission standards.

ARCO????? Man -o Days.... Here in Lancaster, PA those ARCO gas stations are LOOOOOOOOOOOOOOONG gone. Back in the 70's here ARCO was all over.... One by one they began to disappear... Now they are gone. I thought ARCO was no more..... I used to work for the only Shell station in the area when I was in HS, they went belly up, but Shell I know is still around....
 
1 - 20 of 65 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top