Lexus IS Forum banner

61 - 80 of 82 Posts

·
Registered
Joined
·
2,095 Posts
Costco makes my car throw a CEL for fuel evap. I think the code was P0440, but I could be wrong. and yes, it was costco's premium (91 here in AZ).

wish I could find 93 octane here.
I have run costco premium, Shell and BP premium and others. All premiun, but cant tell any difference in performance or mileage. Probably use costco 50% of the time though. No codes that are gas specific.
 

·
Registered
Joined
·
2 Posts
Reg/premium

I have a 2002 IS300 Sportcross. My mom put gas in it a day ago... she used regular and mines premium obviously. Is that terrible for my car using reg once? What do i do if anything?
 

·
Exclusive Agent
Joined
·
3,582 Posts
Discussion Starter #64
I have a 2002 IS300 Sportcross. My mom put gas in it a day ago... she used regular and mines premium obviously. Is that terrible for my car using reg once? What do i do if anything?
You don't need to do anything really. I would run it normally down to E an full up with premium. If you are worried you could probably add an octane booster from autozone, but not really needed.


Sent from AutoGuide.com App
 

·
Registered
Joined
·
30 Posts
I have been running into issues with fuel mileage getting worse...down to 16.5mpg, and 02 Sensor error codes, multiple cylinder misfire codes, and shuttering. Plugs are within 10k miles, all full maintenance has been done. On a whim, I sprung for 93 non-ethanol gas. Within 4 tanks, mileage went from 16.5 city to 20.5. The CEL is off, no more 02 sensor codes, shaking, studdering, misfire codes etc. Seems the Ethanol was just brutally killing my engine. Not saying that is going to be the case for everybody, but wow, non ethanol is a different beast. Feels like I have more power and quicker response. Maybe injectors arent so clogged up.
 

·
Registered
Joined
·
17 Posts
Whats the average miles you guys get with just city driving? I dont know if mine is normal or not. Its an 01 with 157k on it
 

·
Registered
Joined
·
2,095 Posts
Whats the average miles you guys get with just city driving? I dont know if mine is normal or not. Its an 01 with 157k on it
18 - 19 around north Dallas, lights and stop and go mixed.

23 - 25 hi-way at up to 80 mph
 

·
Registered
Joined
·
89 Posts
basically 91 octane is the minimum....These engine were designed originally to run on 95 octane as japanland not only has better cars but better gas as well...
If you run less the engine will just retard the timing to prevent pinging and detonation..

MOre timing increases cylinder pressure which in turn produces more power, and the opposite is true as well.....
Are you sure it's not the same as the US? It's been years since I read or knew the details of this but in England I think it's 91 93 and 95 (something like that) but they measure it different. So 91 in England is the equivalent of 87 in the US.

I haven't owned this car long and have been using 89 but I guess I'll start using 91. I get 18mpg
 

·
Registered
Joined
·
2,095 Posts
Are you sure it's not the same as the US? It's been years since I read or knew the details of this but in England I think it's 91 93 and 95 (something like that) but they measure it different. So 91 in England is the equivalent of 87 in the US.

I haven't owned this car long and have been using 89 but I guess I'll start using 91. I get 18mpg
You are right.

The octane is measured by two different techniques.
RON Research Octane Number Used in Europe and some of the rest of the world.
MON Motor Octane Number
(R+M)/2 is used in USA, you will sometimes see this on the pump, Or AKI Anti-Knock Index.
From what I remember my Sunny specified RON 91 or regular in Singapore, so I suspect its the same in Japan, RON that is.
 

·
Registered
Joined
·
229 Posts
Yeah, I run Petro Canada 94 Octane and although I get some serious power the mileage is crappy. Hahaha and I have an 03 GGP w LSD from US MODEL and everything is in Miles.. I hate it but ah well...
 

·
Registered
Joined
·
7 Posts
today's gas already has additives to keep fuel systems clean, imo the whole additive market snake oil.
That is true. Now there is a difference between summer and winter gasoline (colder climate areas where there is snow). Example A: Summer fuel has 5% alcohol to absorb moisture from the tank and fuel system in your car. Example B: Winter fuel has 20% alcohol to absorb the moisture since there is higher moisture content in the winter (SNOW). Now don't quote me 100% on the numbers because I do not know the exact ratio the fuel companies put in their mixtures but there is a difference between the summer and winter. I had myself an 02 Chrysler 300m with the 3.5L High Output motor... regular 87 octane... summer I usually got 20-22 mpg per tank and winter was 16-18. Since there is more alcohol in the winter it doesn't burn as efficiently hence the 16-18 mpg.

So with that said I am a proud new owner of an 02 IS300 Silver on Black full leather and stock... no mods as of yet. I am running on 89 octane (which is a blend of 87 and 93 at Shell which is the only fuel I use) and had been for a month that I have had the car.... never had any knocking or performance issues. So to each his own... IMO I will keep running mid-grade until the car rusts apart.
 

·
Registered
Joined
·
58 Posts
most of the time i will use 91 octane from valero and it get good gas mileage. on this last tank however i used 93 no ethanol gas, and let me tell you what!! Gas with no ethanol is so much better for the car! Idle is so much smoother and power is more linear.
 

·
Registered
Joined
·
373 Posts
I just filled up with 93 Octane at a Shell station. Cost me $48. Only got me 19mpg highway, maybe a little more since there was maybe a gallon or two left in the tank when I went back to the gas station. Got about 325 miles out of the trip before going back to the gas station.

Edit: I thought our gas tank was 17 gallons, I guess its 15. So if that's try, that's about 21mpg highway. Probably closer to 23 if I actually drove it until the gas ran out.

Edit 2: I have a 2003 5MT MSM IS300 with 175K Miles.
 

·
Registered
Joined
·
562 Posts
Instead of guessing how big the tank is, your calculations would be accurate if you got the receipt off the pump. You would know how many gallons you used, then divide by the miles you drove (hint: use the tripometer).
 

·
Mr. Roo
Joined
·
9,286 Posts
Edit: I thought our gas tank was 17 gallons, I guess its 15. So if that's try, that's about 21mpg highway. Probably closer to 23 if I actually drove it until the gas ran out.
It's definitely more than 15. I believe it is 17, or 17.5 (edit, just looked at the owner's manual, it is 17.5)

IMG_1274

I've filled up 16.647 gallons before.
 
61 - 80 of 82 Posts
Top