I Know You Heard This Before But...gs400 Gas Mileage

[BlexusGS]

Hello,

I noticed for the last year I have been getting really bad gas mileage. I only get around 220 - 240 miles per tank! I do mostly city driving (only about 8 miles/day highway driving). I installed Torque Master spark plugs about 4 months ago and the gas mileage "seems" to have gotten worse. Then I cleaned my K & N air filter, the MAF sensor and throttle body (and re-set the ECU) about 1 month ago... still no help. The other day I put Techron fuel system cleaner...still no help. I have about 87K on my car and it runs great! I just hear on this forum and the CL forum that members with GS4xx's are getting at least 300 miles per tank and that's with heavy driving. I don't remember when I changed the fuel filter though. Can a dirty fuel filter make this much of a drastic difference?

Thanks for the help guys,

Nick

[BlexusGS]

Any suggestions???

[dcfish]

Any suggestions???

It is to my understanding that any plug other than OEM can raise hell with these motors. I don't know if that is your problem but those plugs can't help.

[stroked4.6]

A dirty fuel filter will definitely reduce your fuel economy, it also puts more strain on your pump. You might also want to make sure your tire pressure is at the specified mark. Techron is a very good treatment, I also add that to my cars.

A couple other things to mention about gas mileage is the winter. Since its been cold have you been warming your car up in the morning or keeping it at idle more? This will drastically reduce your gas mileage but you have to do it. Another thing is they add some other additives to the fuel in the winter which also decrease fuel mileage.

I would change the plugs and put the NGK's in there.

[djspawn00]

Thats the mileage i get on my 02 gs300.. then again i drive 100 miles a day during which I'm cruising between 85-90mph most of the time. Check your fuel filter, tire pressure and avoid jackrabbit starts... also make sure you didn't leave and anchor or something in your trunk.

[BlexusGS]

I will check he fuel filter then go from there. Maybe I will change out my TM plugs and drop NGK's back in. BTW I do have a real heavy sub box in the trunk but the spare tire is out. I'm just real concerned with my gas mileage because I am dropping in my 3.76 LSD soon and putting my 19"s back on again since the weather is getting nicer out.

[djspawn00]

I'm not 100% certain but wasn't there something odd about the GS's fuel filter, like it being a nonservicable part or something? Back to the issue on hand, Nick did you always get poor fuel consumption or is it only recently? I live on Long Island also and my past few fill ups have shown me numbers of 15mpg which is the worst I've ever gotten. I do accelerate hard but I think there is just more ethanol than usual in the gas come winter time.

[BlexusGS]

As long as I could remember I have never gotten more than 260 miles out of a tank (unless on long trips of highway driving where I would see as much as 350 miles on a tank!). Now I might get 230 no matter how lightly I drive. I thought when I had cleaned my TB (which was pretty dirty) that I would get better gas mileage...not so. I am going to bring it in for service to check on the fuel filter, TB, sensors and thermostat this weekend. BTW, where on LI do you live? Send PM if you want...

[DrZaius7]

With regards to the Fuel Filter, (I have a 2002 GS430) I know that the fuel filter is a lifetime filter. I asked the dealer to change it during my last service but they said it was a lifetime filter and didn't need to be replaced.

DrZ

[djspawn00]

Thanks for the confirmation Dr. Z

I reside in Uniondale LI, Get some service done at Ralley In Glen Cove, but commute about 100 miles a day going back and forth to stonybrook. I don't think my driving habits are helping my fuel economy but I'll try driving like a normal person for two tanks and see what numbers i get. I clean my throttle body every 10k (gets really dirty) and change my air filters fairly often. My tire pressure is 31psi (nitrogen) on stock wheels w/ Michellin Exalto's V-rated. I got 16.2mpg on my last tank, but i did some "irregular" driving on that last one, I'll see what I come up with this week.

[dcfish]

Thanks for the confirmation Dr. Z

I reside in Uniondale LI, Get some service done at Ralley In Glen Cove, but commute about 100 miles a day going back and forth to stonybrook. I don't think my driving habits are helping my fuel economy but I'll try driving like a normal person for two tanks and see what numbers i get. I clean my throttle body every 10k (gets really dirty) and change my air filters fairly often. My tire pressure is 31psi (nitrogen) on stock wheels w/ Michellin Exalto's V-rated. I got 16.2mpg on my last tank, but i did some "irregular" driving on that last one, I'll see what I come up with this week.

I have a 98 GS300 and I get 18/ 25, Sometimes I push it and on the highway I can get close to 26-7 on the highway @73-6 mph. I always burn primo, K&N air filter..............???

[djspawn00]

Thanks for the confirmation Dr. Z

I reside in Uniondale LI, Get some service done at Ralley In Glen Cove, but commute about 100 miles a day going back and forth to stonybrook. I don't think my driving habits are helping my fuel economy but I'll try driving like a normal person for two tanks and see what numbers i get. I clean my throttle body every 10k (gets really dirty) and change my air filters fairly often. My tire pressure is 31psi (nitrogen) on stock wheels w/ Michellin Exalto's V-rated. I got 16.2mpg on my last tank, but i did some "irregular" driving on that last one, I'll see what I come up with this week.

I have a 98 GS300 and I get 18/ 25, Sometimes I push it and on the highway I can get close to 26-7 on the highway @73-6 mph. I always burn primo, K&N air filter..............???

I must be doing something dreadfully wrong, hmmm i should get my alignment checked again... or maybe gas on the island just sucks.

[BlexusGS]

I hear that!!! The gas on LI MUST suck! However, this tank I just got around 255 miles. That's the highest I've seen in a while. I've been driving the same way to the same destinations yet I got about 30 more miles out of this tank. I'm really confused....

[djspawn00]

Same here, I just got 260 miles out of my last tank i haven't gone to fill it up yet to get an exact mpg, but i always buy my gas at the same place, Sunoco on Hempstead Turnpike across from the coliseum. If not there then a Shell station on route 347 out in Selden, I'll post my mileage later today.

[BlexusGS]

I'm gonna fill-up today as well. I'll let you know. 347 out in Selden...that's by me!

[djspawn00]

17.45mpg according to my fill up today, its on its way up and on this last tank i did a lot of 80mph+ driving on the northern state, I hope no state troopers read this. I'll try to keep my average speeds around 70mph on the next tank and see if i come up with reasonable numbers. I've noticed a lot of the gs posters are from NY, hey its a small world.

[BlexusGS]

It is a small world indeed... unfortunately, my recent fill-up only yielded me a 14.6 mpg. Still 1mpg better than the previous fill up. Maybe I'll check my tire pressure and/or have my alignment checked. Tires are wearing evenly and properly but I have read somewhere that tire pressure and poor alignment can cost you 2 - 3mpg!

[djspawn00]

I got 18.55 on my last tank and I drove like an old lady for all 293 miles! My alignment and tire pressure is on par, I added two bottles of techron fuel system cleaner (although I shouldn't have OD'd on it they were the smaller bottles) Normally I'd dismiss that mileage as acceptable but I was getting much better mileage before... and gas is above $3 a gallon again! I guess I'll have my o2 sensors checked out next time I'm loitering at my friends shop. BLexusGS, would your LSD affect your mileage? Also I'm running the OEM NipponDenso Iridium plugs did the torquemasters offer any advantage?

[BlexusGS]

Hey,

I didn't install my 3.76 LSD (torsen type) as of yet. I have that and Supra half shafts to still install. It will effect gas mileage by about 1-2 mpg from what I read. The TM's I feel gave a little bit of better response but a lot of people notice "REAL" gains when doing more engine mods such as CAI, FI, headers, exhaust Etc. These plugs burn hotter than all the others therfore making better combustion for better power/response. 18.55 mpg is great BTW! I want to get my car up to that level before I install my LSD or I will be @ the gas station every 10 minutes! LOL!

[BlexusGS]

It's unbelievable when you throw some more highway into the mix. I'm just about empty now and I got 270 miles on this tank!!! I normally only get 220 - 240 on a tank. The other day I drove about 70 miles (all highway). My driving usually only consists of about 20% highway and 80% local driving. Have to start riding my bike around town!!! LOL!!!

[djspawn00]

my numbers were pulled with mostly all highway driving... although i've been driving my mazda all this week as i'm going to be doing some majoy DIY work on it with little experience so i figured I'd try to enjoy it before i possibly break it.

[BlexusGS]

Before you break it... <---that's pretty funny!!!LOL!!! I used to do this same thing when I was 10. I would take EVERYTHING apart in my parents house (in working condition) to see how it works. I'de put it back together and no more work! My mom was always *BLEEP*ed at me. Sorry, that just brought back some memories...

[djspawn00]

The weather sucks so my plans are postponed, I drove the GS today, about 150 miles today, refilled my tank at 240 miles. This was the tank that I had added the Chevron Techron fuel system cleaner to, I pulled 16.95mpg but also got a surprise when i checked my oil and saw that it was a quart low, it was never low before. I'm gonna change my oil tommorow and see how my numbers progress.

As far as the mazda, its gonna have to wait til sunny skies come around to be my guinea pig.

I'm going to increase my tire pressure 4psi to 35psi front and rear.. i have oe wheels with oe sized tires I'm just curious to see what this might do.

[BlexusGS]

Good idea...I'm going to check my tire pressure and oil this weekend. Actually, I have an appointment at the Smithtown Lexus Stealership on Saturday. I need an oil change and I want them to check my car for any error codes or anything that can cause poor gas mileage. I'll let you know what I find.

[djspawn00]

Good idea...I'm going to check my tire pressure and oil this weekend. Actually, I have an appointment at the Smithtown Lexus Stealership on Saturday. I need an oil change and I want them to check my car for any error codes or anything that can cause poor gas mileage. I'll let you know what I find.

How's the service at smithtown? An oil change at Rallye is about $120 and i think they use plain old dino juice.