Premium fuel – for ’03-’05 owners ONLY (1 Viewer)

[chrisbruck]

So I’ve read all the debate on the premium vs regular gas in the search fields. I have a question SPECIFIC to the ’03-’05 years only (5spd auto, non-VVT).

I put a tankful of 93 octane in my ’04 that I had previously only used 87 octane and seems noticeably more peppy when you get on the throttle. Not enough miles yet to compare MPG but it’s looking like 1 MPG better.

Curious, have others noticed this as well or is it all in my head?

 

[ENGINE er]

In any car, if it senses knock it will pull timing and this will hurt MPGs and power.

This goes for just about any computer controlled fuel injected car. Run crummy gas and it knocks a lot sooner than if you run a premium fuel.

 

[OregonLC]

Seems consistent with other data: minor improvement in mileage offset by minor increase in cost.

 

[lhfungo]

I have an '04. It has 91k and I bought it with 82k about a year ago. I run 87 from Costco except for when towing or long road trips. That's when I'll use 91 (CA). While running 87 around town and for shorter trips I find no downside. There is no pre detonation and since I'm light on the skinny pedal, I can't really comment on the overall throttle response or "peppiness".

 

[Sandroad]

I've a 2004 and now run premium all the time. At the number of miles I drive it per year and the cost differential, it costs me at most less than $100 per year extra. I'm pleased (as much as is possible) with the gas mileage and performance. Like others, I may have seen (or imagined) a slight improvement in mpg with 93 octane, but it's been too long for me to remember the specifics.

 

[chrisbruck]

After running the numbers on my estimated yearly mileage, I'm looking at only an extra $200 per year for premium. Not as big of a deal as I thought. I do like the extra oomph at throttle tip in but I'll go drive my 911 if I really want some oomph.

 

[SWUtah]

I run premium in my 2005 increases my mpg by "1" mpg. So based on the cost difference between regular and premium, it's a wash. Figure if cost is a wash and Lexus recommends 91 then it's better to use premium.

 

[OregonLC]

I suppose even though cost is a wash, it does increase your range by about 6% which would be an extra 20 miles. Or two fewer trips to the gas station per year, whatever your time is worth. I doubt it has the same improvement off road.

 

[RobRed]

Go mix a half tank of 91 and the other half 104 (race gas) and then report It's like a whole new truck. the 104 is about 7 a gallon compared to $4 for the 91 but for the next 250 miles you'll be a happy guy.

 

[oftpiste]

Go mix a half tank of 91 and the other half 104 (race gas) and then report It's like a whole new truck. the 104 is about 7 a gallon compared to $4 for the 91 but for the next 250 miles you'll be a happy guy.

Can you use octane boost instead? My local Chevron is all out of 104 this week!

 

[mtnracer]

There is definitely a noticeable difference in performance and gas mileage going from 87 to 93. I stick with 93 whenever possible. The extra cost is made up mostly with better mpg and better throttle response.

I also tried various octane boosters, even using my own concoctions but it never really made any difference. The only real gain is with premium gas.

 

[RobRed]

Can you use octane boost instead? My local Chevron is all out of 104 this week!

No. You need the real deal.