Regular gas or Premium? (1 Viewer)

[slowhogg]

My 2004 GX has been getting 13-13.5 MPG in combined driving since I got it back from my daughter who drove it at college. We bought it in 2015 and have always put regular gas, not premium in it. We have had no issues doing this but she only drove 30k miles in 3.5 years and I never checked the mileage. Now that I'm going to daily drive it instead of my 2008 Tundra, I'm wondering if I would get better mileage using premium or would it be negated with the higher fuel price?

Anyway, What is everyone running in these older GX's and does anyone have a real comparison for fuel grades vs mileage?

Thanks!

 

[Tips Up]

My mostly stock 2006 gets 18/21. I run regular, cheapest stuff they have at Costco typically. I'm also at 6,600', and my understanding is that high altitude negates any benefits of premium fuel. I have put premium in it many times, don't notice much difference but have not scientifically tracked mpg comparisons.

 

[HomersCanyonero]

My manual (2003) says regular fuel, so I don’t bother with premium.

 

[Bluetribal]

My wife puts cheap 87 octane in when she fills up and I put 91 when I fill it up.

 

[xlx]

I have 2003 and always run 87 regular and get 16-18 mpg with 275 70 17 BFG KO2’s.

 

[Tak555]

haven't read through this entire thread, but check it out:

GX470 - premium fuel??

I'm in the market for a GX470 and ran across a note mentioning the engine requiring premium. Does the GX470 really take premium fuel? Does anyone strictly run regular?

forum.ih8mud.com

 

[CarolinaGX]

I was getting a little over 19mpg with the stock tires on the highway. Mixed driving is really hard to compare because the ratio between city and highway will vary. Also, driving styles such as running up to traffic lights and stopping versus coasting up to them hoping to avoid completely stopping (my approach) will have an effect.

I changed both differential fluids to Mobil1 but I am not sure if that really helped. I will be changing the diff to Royal Purple this week. I have 170k on mine.

 

[GXO]

I get around 14-16 highway on 35s with armor, etc with mid-grade, but I am super PM oriented. Just had new carrier bearings put in. I have rebuilt everything but the engine. Trans wasn't rebuilt, but I did put in a Nomad valve body.

 

[HomersCanyonero]

How is everyone calculating mpg’s when the odometer is off due to larger tires? Using revolutions per mile of oem stock tires vs new tires? Using diameter of tires? Using actual GPS distance divided by gallons used?

I’m getting super crappy mpg’s but I haven’t taken into account the larger tires.

 

[vwynn]

ive noticed (for me at least) my MPG on my computer is as accurate as calculating the actual via phone once i installed my 285/70/17 lol... or at least close..

Computer says 14.2 mpg... and my actual would read 14.3 after i factor in the ~7% increase of OD from the 33"s

i roll with 87 @ costco cuz its like $3.25 per Gallon,.

 

[HomersCanyonero]

I’m going to start tracking my odometer miles and gallons filled/used for a few months.

I calculated that oem stock tires 265/65R17s had 682 revs per mile (per tire site) and my Nitto Ridge Grapplers 285/70R17 say 634 revs per mile. 682/634=1.0757

So, I’ll adjust my miles by that factor when calculating MPG

 

[GXO]

I use a GPS on my ipad with a trip tracker to do my mpgs. I don't even look at that computer thingy. I have it set to time and temp always lol

 

[ATKIJACO]

How would the non ethanol gas run in a GX?

 

[Dharma Dude]

I get 16 mpg (based on GPS) on my camping trips. But I stick to the speed limit everywhere.

I only run 87. My GX has 315/70R17 (34.4 inch tires), regeared to 4.56. Fully armored, Not my daily driver, so I don't drive it much in the city. The mpg is lower in the city but I don't track it.

I doubt very much running premium would get any mpg advantage.

 

[dynacomp2002]

First post on these forums. I read through the other thread about premium fuel from a few years ago.
It seems to depend on what year your GX is. I tried out an eighth of a tank of 87 this morning, and I could feel and hear the difference. The engine didn't sound bad, just not as smooth as it was before. This evening, I filled up on 93 (low fuel warning light was on), and in a few minutes the sound and feel was back to normal. I have a 2007 model. Have had it for two weeks now, and loving it!

 

[Dharma Dude]

First post on these forums. I read through the other thread about premium fuel from a few years ago.
It seems to depend on what year your GX is. I tried out an eighth of a tank of 87 this morning, and I could feel and hear the difference. The engine didn't sound bad, just not as smooth as it was before. This evening, I filled up on 93 (low fuel warning light was on), and in a few minutes the sound and feel was back to normal. I have a 2007 model. Have had it for two weeks now, and loving it!

You need to do a double blind test.

 

[ChaseTruck]

'04, 265/70/17 tires, stock everything, 13.5-15mpg, always premium fuel.
I've filled up with 87 once, and she responded by throwing an oxygen sensor code...

 

[IanB]

How is everyone calculating mpg’s when the odometer is off due to larger tires? Using revolutions per mile of oem stock tires vs new tires? Using diameter of tires? Using actual GPS distance divided by gallons used?

I’m getting super crappy mpg’s but I haven’t taken into account the larger tires.

We have odometer test signs along our highways here, 10kms marked out so you can see how far off your odometer is from accurate. I calculated a 1.05 correction factor running 265/70/17's and 1.03 when running 265/65/17's on my GX.

 

[nikramos]

I have an 06 and filled it up with 87 since premium is now 4.65 per gallon in SF BayArea . Noticeable difference in power loss. Sluggish throttle response.
Going back to Premium. My VVTi does not like Regular

 

[Dharma Dude]

I have an 06 and filled it up with 87 since premium is now 4.65 per gallon in SF BayArea . Noticeable difference in power loss. Sluggish throttle response.
Going back to Premium. My VVTi does not like Regular

I must drive differently because I have never noticed any performance difference in 87 or premium. Seems exactly the same to me. I'm sticking with regular. Never noticed any mpg difference either, and I have tried different gas brands.