Gs 400 Only Under 200 Miles On A Tank?!

[Lexus_gs400]

I think I may have a HUGE problem. I drive my car on the local only, and it only hits under 200 miles before I have to re-fuel again... and what is an O2 sensor?? Will this be the problem or a new gas tank?? Thanks guys

[Wicked_Lex]

I don't know much about the O2 sensor or how it would effect mileage but if you are in a lot of stop-and-go trafic you won't get good mileage. One of the most determing factors in MPG is the way that someone drives. When I first got my GS I was getting less than 200 miles per tank because I was doing a lot of 0-60 shots, and jamming the pedal down to get around slow moving trafic. Recently I took a trip from California to the Midwest , set cruise control at 75-80 MPH, and still got 25 or 26 MPG!

Less than 200 miles on a tank doesn't sound right unless you're driving fast in the city. I think the GS gas tank holds around 18 gallons so you'd only be getting about 10-11 MPG. Just a few questions:

1) What is the vehicle mileage and when is the last time it was tuned?

Fouled plugs, defective plug wires, and dirty air filters can rob mileage.

2) What kind of tire pressure are you runnig?

Most tires recommend 32 LBS but I run mine at 35-36 because it coasts better

and still gives a good ride. If you have one or more tires at 25 LBS or less

you're wasting fuel.

3) What grade of fuel are you burning?

There is a temptation to burn cheaper grades now that gasoline is over $3/gallon

If you're not burning at least 91 octane in your Lexus you won't get the

performance/mileage that the engine was designed for.

A few other suggestions:

Use synthetic oil - less resistance means slightly better performance and mileage

Don't drive with the tranny in power mode or use the select shift.

If none of this helps I'd go to your Lexus dealor and have them put it on a scope. You might have a defective computer chip. I hope that isn't the case, it might cost you a couple of paychecks.

[Lexusfreak]

Agreed, good advice!

What's the mileage on the car? As mentioned, a major tune up might be in order & make sure those tire pressures are at the proper levels. B)

[Lexus_gs400]

I don't know much about the O2 sensor or how it would effect mileage but if you are in a lot of stop-and-go trafic you won't get good mileage.  One of the most determing factors in MPG is the way that someone drives.  When I first got my GS I was getting less than 200 miles per tank because I was doing a lot of 0-60 shots, and jamming the pedal down to get around slow moving trafic.  Recently I took a trip from California to the Midwest , set cruise control at 75-80 MPH, and still got 25 or 26 MPG!

Less than 200 miles on a tank doesn't sound right unless you're driving fast in the city.  I think the GS gas tank holds around 18 gallons so you'd only be getting about 10-11 MPG.  Just a few questions:

1) What is the vehicle mileage and when is the last time it was tuned?

    Fouled plugs, defective plug wires, and dirty air filters can rob mileage.

2)  What kind of tire pressure are you runnig?

      Most tires recommend 32 LBS but I run mine at 35-36 because it coasts better

      and still gives a good ride.  If you have one or more tires at 25 LBS  or less

      you're wasting fuel. 

3) What grade of fuel are you burning? 

    There is a temptation to burn cheaper grades now that gasoline is over $3/gallon

    If you're not burning at least 91 octane in your Lexus you won't get the

    performance/mileage that the engine was designed for.

A few other suggestions:

Use synthetic oil - less resistance means slightly better performance and mileage

Don't drive with the tranny in power mode or use the select shift.

If none of this helps I'd go to your Lexus dealor and have them put it on a scope.  You might have a defective computer chip.  I hope that isn't the case, it might cost you a couple of  paychecks.

←

The car has 52K on it. I buy 93 for my car or in Mobil it's super. The car hasn't been tuned yet for anything major, Because my the dealer told me to come back at 60k before any tune up is required.

I have changed all 8 Spark plugs to DENSO 4 months ago.

I also do an oil change every 1500 miles with Mobil 1.

I have just changed the air filters from stock to TRD 2 months ago.

I also Don't drive with the tranny in power mode or use the select shift.

Maybe it is because I drive local everyday, But I only use under 5 miles everyday from home to work and I do only go 30-44 when going to work. I just feel it's weird because GS 400 and 430 have 19.8 gallons on the tank and even if I do 10 miles per gallon I should still run 190 or up.. I'm at 65.4 now on the meter and I have used alittle more than 1/3 of the gas.

Let's just say if I do have to go to Lexus to get the computer chip replaced, How much would it run me? Thanks guy you been alot of help.

[Wicked_Lex]

[

The car has 52K on it. I buy 93 for my car or in Mobil it's super. The car hasn't been tuned yet for anything major, Because my the dealer told me to come back at 60k before any tune up is required.

I have changed all 8 Spark plugs to DENSO 4 months ago.

I also do an oil change every 1500 miles with Mobil 1.

I have just changed the air filters from stock to TRD 2 months ago.

I also Don't drive with the tranny in power mode or use the select shift.

Maybe it is because I drive local everyday, But I only use under 5 miles everyday from home to work and I do only go 30-44 when going to work. I just feel it's weird because GS 400 and 430 have 19.8 gallons on the tank and even if I do 10 miles per gallon I should still run 190 or up.. I'm at 65.4 now on the meter and I have used alittle more than 1/3 of the gas.

Let's just say if I do have to go to Lexus to get the computer chip replaced, How much would it run me? Thanks guy you been alot of help.

It sounds like you are doing all the right things but even in heavy traffic you should still get 4-5 more MPG than you are. The fuel mixture might be too rich, that is all controlled by the computer too. Does it blow any dark colored smoke out of the exhaust? If you have time you might take it out on the highway, set you trip odometer, fill up with gas, travel a distance at cruising speed, fill it up again and do the math. If your getting over 20 MPG there is probably not much wrong with the car. Otherwise I would go to the Lexus dealership. One more thing – hope that you don’t need a new ECU. I was reading one of the threads and some guy, not sure what model, said it costs - $3000!!!!!

[Lexus_gs400]

[

The car has 52K on it. I buy 93 for my car or in Mobil it's super. The car hasn't been tuned yet for anything major, Because my the dealer told me to come back at 60k before any tune up is required.

I have changed all 8 Spark plugs to DENSO 4 months ago.

I also do an oil change every 1500 miles with Mobil 1.

I have just changed the air filters from stock to TRD 2 months ago.

I also Don't drive with the tranny in power mode or use the select shift.

Maybe it is because I drive local everyday, But I only use under 5 miles everyday from home to work and I do only go 30-44 when going to work. I just feel it's weird because GS 400 and 430 have 19.8 gallons on the tank and even if I do 10 miles per gallon I should still run 190 or up.. I'm at 65.4 now on the meter and I have used alittle more than 1/3 of the gas.

Let's just say if I do have to go to Lexus to get the computer chip replaced, How much would it run me? Thanks guy you been alot of help.

It sounds like you are doing all the right things but even in heavy traffic you should still get 4-5 more MPG than you are.  The fuel mixture might be too rich, that is all controlled by the computer too.  Does it blow any dark colored smoke out of the exhaust?  If you have time you might take it out on the highway, set you trip odometer, fill up with gas,  travel a distance at cruising speed, fill it up again and do the math.  If your getting over 20 MPG there is probably not much wrong with the car.  Otherwise I would go to the Lexus dealership.  One more thing – hope that you don’t need a new ECU.  I was reading one of the threads and some guy, not sure what model, said it costs    -  $3000!!!!!

←

Actually it blows clear smoke so I figure the car is still good. I went to New Jersey to fill up before the New Orleans accident happen and got a good 70HWmiles coming back to New York. That only used up 2/10 of gas, but then after another 100miles of so, GAS ALL GONE.. I'll take it to Lexus on monday morning. $3000. Damn that's alot of money.. I'll let you guys know how everything is after I get back for Lexus, Anyways thanks for the advice.

[Wicked_Lex]

One more thing – hope that you don’t need a new ECU.  I was reading one of the threads and some guy, not sure what model, said it costs    -  $3000!!!!!

Actually it blows clear smoke so I figure the car is still good. I went to New Jersey to fill up before the New Orleans accident happen and got a good 70HWmiles coming back to New York. That only used up 2/10 of gas, but then after another 100miles of so, GAS ALL GONE.. I'll take it to Lexus on monday morning. $3000. Damn that's alot of money.. I'll let you guys know how everything is after I get back for Lexus, Anyways thanks for the advice.

Before you panic about the $3000, there is something I forgot to mention. From what I've heard about ECUs, which isn't very much, some of them are modular in design. What I mean by this is that they are composed of multiple subsystems that control various functionalities and act independently, meaning if one part of the ECU is bad you just replace that part of it. I don’t know if the Lexus ECU is like that or not. If it is, then you may get lucky and only have to replace the defective part if that is what's causing the problem. In that case the cost may be closer to $300 than $3000. There are probably a lot of members who know something about ECUs and might respond if you started a new thread.

[Abear]

I dont know anything about the ecu of the car, and I'm not driving a 400 either, but I do know a little about the O2 sensor. If your O2 sensor is bad it wont work..lol obviously. If the O2 sensor isnt working it cant read how much air is coming out of the exhaust, causing the car to not know how much fuel to add. If it is adding too much fuel, well you see where Im going. Also, the air coming out of the exhaust will be a little dark, but you cant just turn the car on and let it idle to find this out, you have to rev it up a little bit. Hope this helps, and keep is informed as to what the dealer says. Also, forget to say, O2 sensors arent that expensive, less than $100.

[SKperformance]

so what is your tire pressures?

I find that a 10-15% difference in economy.

I get 700 km per tank with my city /highway mix with my 98 LS400 which is almost the same with my civic.

Intake ,exhaust, lowered 1.5inches and 50lbs of tire pressure.

[Lexus_gs400]

One more thing – hope that you don’t need a new ECU.  I was reading one of the threads and some guy, not sure what model, said it costs    -  $3000!!!!!

Actually it blows clear smoke so I figure the car is still good. I went to New Jersey to fill up before the New Orleans accident happen and got a good 70HWmiles coming back to New York. That only used up 2/10 of gas, but then after another 100miles of so, GAS ALL GONE.. I'll take it to Lexus on monday morning.  $3000. Damn that's alot of money.. I'll let you guys know how everything is after I get back for Lexus, Anyways thanks for the advice.

Before you panic about the $3000, there is something I forgot to mention.  From what I've heard about ECUs, which isn't very much, some of them are modular in design.  What I mean by this is that they are composed of multiple subsystems that control various functionalities and act independently, meaning if one part of the ECU is bad you  just replace that part of it.  I don’t know if the Lexus ECU is like that or not.  If it is, then you may get lucky and only have to replace the defective part if that is what's causing the problem.  In that case the cost may be closer to $300  than $3000.  There are probably a lot of members who know something about ECUs and might respond if you started a new thread.

←

I do have a couple of things done to my car,

1. Tom's side blinking mirrors.

2. Jdm grounding kit with box

3 etc...

Will Lexus still repair the car if I did change alittle things left and right or I can just ask my friend to order it from Lexus and have him install it? Thanks

[Lexus_gs400]

I dont know anything about the ecu of the car, and I'm not driving a 400 either, but I do know a little about the O2 sensor. If your O2 sensor is bad it wont work..lol obviously. If the O2 sensor isnt working it cant read how much air is coming out of the exhaust, causing the car to not know how much fuel to add. If it is adding too much fuel, well you see where Im going. Also, the air coming out of the exhaust will be a little dark, but you cant just turn the car on and let it idle to find this out, you have to rev it up a little bit. Hope this helps, and keep is informed as to what the dealer says. Also, forget to say, O2 sensors arent that expensive, less than $100.

←

Let's just say the 02 sensor is bad. Do I have to take it to Lexus to get it changed or I can order it myself and have someone else put it on? Thank you

[Lexus_gs400]

so what is your tire pressures?

I find that a 10-15% difference in economy.

I get 700 km per tank with my city /highway mix with my 98 LS400 which is almost the same with my civic.

Intake ,exhaust, lowered 1.5inches and 50lbs of tire pressure.

←

I haven't check my tire pressure in 2 weeks, So I'm not sure yet. I haven't got Intake or exhaust yet. I had a civic before and it made tooooo much noise for me to handle, That's why I lefted it stock. But they do say SRT intake will save some gas mileage and it will still be quite as the stock air filter?? If that is true I'll think about getting it. I was actually on lextasy.com and thinking about this item SRT intake. Please guys what do you think. I really don't need more horse power because I drive local everyday 7 days a week. maybe a GS 300 would have been better? But the GS 400 sounds better. Thanks

[Wicked_Lex]

[

I haven't check my tire pressure in 2 weeks, So I'm not sure yet. I haven't got Intake or exhaust yet. I had a civic before and it made tooooo much noise for me to handle, That's why I lefted it stock. But they do say SRT intake will save some gas mileage and it will still be quite as the stock air filter?? If that is true I'll think about getting it. I was actually on lextasy.com and thinking about this item SRT intake. Please guys what do you think. I really don't need more horse power because I drive local everyday 7 days a week. maybe a GS 300 would have been better? But the GS 400 sounds better. Thanks

Call auto parts stores to find cost of O2 sensor and repair shops for installation estimate. Lexus dealership will most likely be the most expensive but there is some work that will only be done by them. I’ve just ordered my SRT intake so I can't tell you how it sounds. If you have stock exhaust it probably won't be real loud. I have heard that it marginally boosts MPG, but I bought it because it give the most HP bang for the buck. As far as the buying the GS300 instead: a properly running GS400 isn’t going to burn much more gas and will give you the power when you need it. Once you get your mileage problem solved you won’t be happy with the milder performing 300.

[Lexus_gs400]

[

I haven't check my tire pressure in 2 weeks, So I'm not sure yet. I haven't got  Intake or exhaust yet. I had a civic before and it made tooooo much noise for me to handle, That's why I lefted it stock. But they do say SRT intake will save some gas mileage and it will still be quite as the stock air filter?? If that is true I'll think about getting it. I was actually on lextasy.com and thinking about this item SRT intake. Please guys what do you think. I really don't need more horse power because I drive local everyday 7 days a week. maybe a GS 300 would have been better? But the GS 400 sounds better. Thanks

Call auto parts stores to find cost of O2 sensor and repair shops for installation estimate.  Lexus dealership will most likely be the most expensive but there is some  work that will only be done by them.  I’ve just ordered my SRT intake so I can't tell you how it sounds.  If you have stock exhaust it probably won't be real loud.  I have heard that it marginally boosts MPG, but I bought it because it give the most HP bang for the buck.  As far as the buying the GS300 instead: a properly running GS400 isn’t going to burn much more gas and will give you the power when you need it.  Once you get your mileage problem solved you won’t be happy with the milder performing 300.

←

Thanks. But do you know what kind of work will be performed by Lexus if I buy the 02 sensor from somewhere. If it's really a hassle, I'll just take it to Lexus and let them do all the work there is need. By the way how much did you pay for your SRT intake? Thanks

[Wicked_Lex]

Thanks. But do you know what kind of work will be performed by Lexus if I buy the 02 sensor from somewhere. If it's really a hassle, I'll just take it to Lexus and let them do all the work there is need. By the way how much did you pay for your SRT intake? Thanks.

I'm not sure, but I don't think Lexus is going to be too cool about buying somebody else’s part and then asking them to install it. Especially if it is NOT an OEM part. The first thing that you need to do before buying any parts is find out what the problem is. See if you can talk to one of the Lexus technicians after explaining that you bought THEIR car. Tell the tech what the problem is and ask him if it sounds like the O2 sensor might be the problem. Most likely he’ll say ‘bring it in and we’ll take a look at it’. If he says ‘Yep sounds like the O2 sensor is fried’ ask him what it will cost and compare that to other shops. But I would still have it diagnosed FIRST.

Lexus gives great service but they are very expensive. When I had my ES I called and asked what the price would be to replace the struts since the car had about 100K miles and OEM struts. Lexus said it would be about $1200 + $100 for an alignment. I shopped around and found a shop that used better parts and got it out the door for about $750, more than $500 less than Lexus. However, since the O2 sensor is part of the ECU other shops might not want to touch that.

As for your question about the SRT intake, I bought mine at www.Lextasy.com

for $445, which is $50 less than buying directly from Swift!

[Lexus_gs400]

Thanks. But do you know what kind of work will be performed by Lexus if I buy the 02 sensor from somewhere. If it's really a hassle, I'll just take it to Lexus and let them do all the work there is need. By the way how much did you pay for your SRT intake? Thanks.

I'm not sure, but I don't think Lexus is going to be too cool about buying somebody else’s part and then asking them to install it.  Especially if it is NOT an OEM part.  The first thing that you need to do before buying any parts is find out what the problem is.  See if you can talk to one of the Lexus technicians after explaining that you bought THEIR car. Tell the tech what the problem is and ask him if it sounds like the O2 sensor might be the problem.  Most likely he’ll say ‘bring it in and we’ll take a look at it’.  If he says ‘Yep sounds like the O2 sensor is fried’ ask him what it will cost and compare that to other shops.  But I would still have it diagnosed FIRST.

Lexus gives great service but they are very expensive.  When I had my ES I called and asked what the price would be to replace the struts since the car had about 100K miles and OEM struts.  Lexus said it would be about $1200 + $100 for an alignment.  I shopped around and found a shop that used better parts and got it out the door for about $750, more than $500 less than Lexus.  However, since the O2 sensor is part of the ECU other shops might not want to touch that.

As for your question about the SRT intake, I bought mine at www.Lextasy.com

for $445, which is $50 less than buying directly from Swift!

←

Thanks alot for your help"_"