Gas Mileage on 1999 RX 300

Post by a***@att.net
My 1999 RX 300 has a very poor gas mileage, the best I get is 16 MPG,
I have a mechanic look at it and they replaced the spark plugs, Tune-
up, fuel injection cleaning and throttle body cleaning, it didn't help
much, I took it back and they don't know what else to do to get better
gas mileage, my wife tells me that it runs litle heavy specially when
you turn the car, I didn't feel it, someone told me 99 has
transmission issues and that might be a problem. I am at lost now,
please help.
Abid

It sounds like it is your wife's driver. If so, I'd swap vehicles
for a while to eliminate/expose any driving habit variables.

Additionally, is you '99 RX300 suppose to get significantly
better mileage that 16?

Ray O

2008-07-01 02:17:09 UTC

What kind of spark plugs were installed?

How many miles on the odometer? It your RX front or all wheel drive?

What type of driving is the vehicle used for? If it is used primarily for
very short trips, the engine will not warm up sufficiently to go into closed
loop operation.

What are the typical driving conditions? City? Highway? Stop-and-go?
What is the terrain like? Are the roads hilly?

What kind of cargo and passengers are typically in the vehicle?

When was the transmission fluid changed and what is the condition of the
automatic transmission fluid?

What pressure are the tires inflated to?

--
Ray O
(correct punctuation to reply)

a***@att.net

2008-07-01 13:07:14 UTC

What kind of spark plugs were installed?
How many miles on the odometer? It your RX front or all wheel drive?
What type of driving is the vehicle used for? If it is used primarily for
very short trips, the engine will not warm up sufficiently to go into closed
loop operation.
What are the typical driving conditions? City? Highway? Stop-and-go?
What is the terrain like? Are the roads hilly?
What kind of cargo and passengers are typically in the vehicle?
When was the transmission fluid changed and what is the condition of the
automatic transmission fluid?
What pressure are the tires inflated to?
--
Ray O
(correct punctuation to reply)

Ray O

2008-07-02 03:49:23 UTC

What kind of spark plugs were installed?
How many miles on the odometer? It your RX front or all wheel drive?
What type of driving is the vehicle used for? If it is used primarily for
very short trips, the engine will not warm up sufficiently to go into closed
loop operation.
What are the typical driving conditions? City? Highway? Stop-and-go?
What is the terrain like? Are the roads hilly?
What kind of cargo and passengers are typically in the vehicle?
When was the transmission fluid changed and what is the condition of the
automatic transmission fluid?
What pressure are the tires inflated to?
--
Ray O
(correct punctuation to reply)

Thanks Ray, odometer reading is 104,000, front wheel drive, mostly
city driving in Houston, TX, short trips, no hills, mostly no cargo,
wife and two kids or all four of us, ATF looks clean but I have no
idea when it was changed, I check the pressure and now it is 32 on all
4 tires, coupld of them were low 27/28.

Abid

***********
Abid,

I think that the mostly short trips, and perhaps a heavy foot, are causing
the relatively poor fuel economy, although according to this EPA web site:
http://www.fueleconomy.gov/feg/bymodel/1999_Lexus_RX_300.shtml

The 1999 RX 300's fuel economy ratings using the new revised (more
realistic) fuel economy estimates are 17 city, 22 highway, so 16 in the city
for mostly short trips is not all that bad.

I would inflate the tires to 35 or 36 PSI cold to improve tire life and fuel
economy.

--
Ray O
(correct punctuation to reply)

a***@att.net

2008-07-02 13:25:43 UTC

What kind of spark plugs were installed?
How many miles on the odometer? It your RX front or all wheel drive?
What type of driving is the vehicle used for? If it is used primarily for
very short trips, the engine will not warm up sufficiently to go into closed
loop operation.
What are the typical driving conditions? City? Highway? Stop-and-go?
What is the terrain like? Are the roads hilly?
What kind of cargo and passengers are typically in the vehicle?
When was the transmission fluid changed and what is the condition of the
automatic transmission fluid?
What pressure are the tires inflated to?
--
Ray O
(correct punctuation to reply)

Thanks Ray, odometer reading is 104,000, front wheel drive, mostly
city driving in Houston, TX, short trips, no hills, mostly no cargo,
wife and two kids or all four of us, ATF looks clean but I have no
idea when it was changed, I check the pressure and now it is 32 on all
4 tires, coupld of them were low 27/28.
Abid
***********
Abid,
I think that the mostly short trips, and perhaps a heavy foot, are causing
the relatively poor fuel economy, although according to this EPA web site:http://www.fueleconomy.gov/feg/bymodel/1999_Lexus_RX_300.shtml
The 1999 RX 300's fuel economy ratings using the new revised (more
realistic) fuel economy estimates are 17 city, 22 highway, so 16 in the city
for mostly short trips is not all that bad.
I would inflate the tires to 35 or 36 PSI cold to improve tire life and fuel
economy.
--
Ray O
(correct punctuation to reply)- Hide quoted text -
- Show quoted text -

Thanks Ray, The link really helps, I will inflate the tires to 35.

Abid

Ray O

2008-07-03 00:35:53 UTC

What kind of spark plugs were installed?
How many miles on the odometer? It your RX front or all wheel drive?
What type of driving is the vehicle used for? If it is used primarily for
very short trips, the engine will not warm up sufficiently to go into closed
loop operation.
What are the typical driving conditions? City? Highway? Stop-and-go?
What is the terrain like? Are the roads hilly?
What kind of cargo and passengers are typically in the vehicle?
When was the transmission fluid changed and what is the condition of the
automatic transmission fluid?
What pressure are the tires inflated to?
--
Ray O
(correct punctuation to reply)

Thanks Ray, odometer reading is 104,000, front wheel drive, mostly
city driving in Houston, TX, short trips, no hills, mostly no cargo,
wife and two kids or all four of us, ATF looks clean but I have no
idea when it was changed, I check the pressure and now it is 32 on all
4 tires, coupld of them were low 27/28.
Abid
***********
Abid,
I think that the mostly short trips, and perhaps a heavy foot, are causing
the relatively poor fuel economy, although according to this EPA web
site:http://www.fueleconomy.gov/feg/bymodel/1999_Lexus_RX_300.shtml
The 1999 RX 300's fuel economy ratings using the new revised (more
realistic) fuel economy estimates are 17 city, 22 highway, so 16 in the city
for mostly short trips is not all that bad.
I would inflate the tires to 35 or 36 PSI cold to improve tire life and fuel
economy.
--
Ray O
(correct punctuation to reply)- Hide quoted text -
- Show quoted text -

Thanks Ray, The link really helps, I will inflate the tires to 35.

Abid

**********
You're welcome! Try to combine the numerous short trips into fewer longer
ones where the engine has a chance to warm up completely. Your fuel economy
should improve a little.

--
Ray O
(correct punctuation to reply)

a***@att.net

2008-07-03 13:52:23 UTC

What kind of spark plugs were installed?
How many miles on the odometer? It your RX front or all wheel drive?
What type of driving is the vehicle used for? If it is used primarily for
very short trips, the engine will not warm up sufficiently to go into closed
loop operation.
What are the typical driving conditions? City? Highway? Stop-and-go?
What is the terrain like? Are the roads hilly?
What kind of cargo and passengers are typically in the vehicle?
When was the transmission fluid changed and what is the condition of the
automatic transmission fluid?
What pressure are the tires inflated to?
--
Ray O
(correct punctuation to reply)

Thanks Ray, odometer reading is 104,000, front wheel drive, mostly
city driving in Houston, TX, short trips, no hills, mostly no cargo,
wife and two kids or all four of us, ATF looks clean but I have no
idea when it was changed, I check the pressure and now it is 32 on all
4 tires, coupld of them were low 27/28.
Abid
***********
Abid,
I think that the mostly short trips, and perhaps a heavy foot, are causing
the relatively poor fuel economy, although according to this EPA web
site:http://www.fueleconomy.gov/feg/bymodel/1999_Lexus_RX_300.shtml
The 1999 RX 300's fuel economy ratings using the new revised (more
realistic) fuel economy estimates are 17 city, 22 highway, so 16 in the city
for mostly short trips is not all that bad.
I would inflate the tires to 35 or 36 PSI cold to improve tire life and fuel
economy.
--
Ray O
(correct punctuation to reply)- Hide quoted text -
- Show quoted text -

Thanks Ray, The link really helps, I will inflate the tires to 35.
Abid
**********
You're welcome! Try to combine the numerous short trips into fewer longer
ones where the engine has a chance to warm up completely. Your fuel economy
should improve a little.
--
Ray O
(correct punctuation to reply)- Hide quoted text -
- Show quoted text -

Stephen Clark

2008-07-03 23:28:03 UTC

<snip>

Abid, I also live in Houston, and my wife's 99 RX gets similar useage as you
describe.

We typically get about 17 MPG in town, and about 21 MPG on a road trip,
both, of course with the A/C on. Recently the mileage gradually dropped to
14.5/19, and a carbon-cleaning procedure and tune-up restored the mileage to
17/21.

See the thread titled "99 RX-300 Ignition Coil Falure " for the full story.

Good Luck!

--
Stephen Clark
99 Lexus RX-300
Houston, Texas USA

Anonymous

2008-07-04 01:14:10 UTC

Post by Stephen Clark
<snip>
Abid, I also live in Houston, and my wife's 99 RX gets similar useage as
you describe.
We typically get about 17 MPG in town, and about 21 MPG on a road trip,
both, of course with the A/C on. Recently the mileage gradually dropped to
14.5/19, and a carbon-cleaning procedure and tune-up restored the mileage
to 17/21.
See the thread titled "99 RX-300 Ignition Coil Falure " for the full story.
Good Luck!
--
Stephen Clark
99 Lexus RX-300
Houston, Texas USA

http://groups.google.com/group/alt.autos.lexus/browse_frm/thread/1d981a2d7ffd0667/ccc4e2a7b38e7064?hl=en%3Fhl&lnk=gst&q=%2B%22coil+failure%22#ccc4e2a7b38e7064

a***@att.net

2008-07-07 14:08:15 UTC

Post by Stephen Clark
<snip>
Abid, I also live in Houston, and my wife's 99 RX gets similar useage as you
describe.
We typically get about 17 MPG in town, and about 21 MPG on a road trip,
both, of course with the A/C on. Recently the mileage gradually dropped to
14.5/19, and a carbon-cleaning procedure and tune-up restored the mileage to
17/21.
See the thread titled "99 RX-300 Ignition Coil Falure " for the full story.
Good Luck!
--
Stephen Clark
99 Lexus RX-300
Houston, Texas USA

Thanks Stephen,

mcbrue

2008-07-07 22:08:44 UTC

Oh good grief !!!! STOP WORRYNG ABOUT MILAGE !!!!!! Just go drive like
you have to. My grandfather only took one trip a week, about 20 miles,
and got excellent milage. He died anyway!!! So just go ahead and burn
up the stupid mid-easterner's gas and oil, and then we will sell them
ours when the price is really high because by that time we will drill
all over the shores and cities and other pretty places because we will
feel comfortable doing it at $1823/bbl.

GIga

2008-07-10 23:31:14 UTC

Wow. Something intelligent from McBrewski. Be still my heart, will wonders
never cease!

GIga

Post by mcbrue
Oh good grief !!!! STOP WORRYNG ABOUT MILAGE !!!!!! Just go drive like
you have to. My grandfather only took one trip a week, about 20 miles,
and got excellent milage. He died anyway!!! So just go ahead and burn
up the stupid mid-easterner's gas and oil, and then we will sell them
ours when the price is really high because by that time we will drill
all over the shores and cities and other pretty places because we will
feel comfortable doing it at $1823/bbl.

Ray O

2008-07-04 02:54:58 UTC

What kind of spark plugs were installed?
How many miles on the odometer? It your RX front or all wheel drive?
What type of driving is the vehicle used for? If it is used primarily for
very short trips, the engine will not warm up sufficiently to go into closed
loop operation.
What are the typical driving conditions? City? Highway? Stop-and-go?
What is the terrain like? Are the roads hilly?
What kind of cargo and passengers are typically in the vehicle?
When was the transmission fluid changed and what is the condition of the
automatic transmission fluid?
What pressure are the tires inflated to?
--
Ray O
(correct punctuation to reply)

Thanks Ray, odometer reading is 104,000, front wheel drive, mostly
city driving in Houston, TX, short trips, no hills, mostly no cargo,
wife and two kids or all four of us, ATF looks clean but I have no
idea when it was changed, I check the pressure and now it is 32 on all
4 tires, coupld of them were low 27/28.
Abid
***********
Abid,
I think that the mostly short trips, and perhaps a heavy foot, are causing
the relatively poor fuel economy, although according to this EPA web
site:http://www.fueleconomy.gov/feg/bymodel/1999_Lexus_RX_300.shtml
The 1999 RX 300's fuel economy ratings using the new revised (more
realistic) fuel economy estimates are 17 city, 22 highway, so 16 in the city
for mostly short trips is not all that bad.
I would inflate the tires to 35 or 36 PSI cold to improve tire life and fuel
economy.
--
Ray O
(correct punctuation to reply)- Hide quoted text -
- Show quoted text -

Thanks Ray, The link really helps, I will inflate the tires to 35.
Abid
**********
You're welcome! Try to combine the numerous short trips into fewer longer
ones where the engine has a chance to warm up completely. Your fuel
economy
should improve a little.
--
Ray O
(correct punctuation to reply)- Hide quoted text -
- Show quoted text -

Good suggession, we will do that, it just that sometime short trips is
all we have to do, drop off kid to a friends house, pick up movies or
food from Mc Donalds, quick stop to grocery store to pickup milk,
stuff like that, but with the gas price these days, we will make fewer
short trips, BTW my MB E500 gives me 18/19 in City and 23/24 on High,
bigger engine more HP - go figure.

Abid

***************
I'm getting 18 to 19 MPG in suburban driving and 21 ~ 16 in highway driving
in my LS 430. I think the bigger engine doesn't have to work as hard as the
smaller one, and a light foot results in decent mileage like you are getting
in your Mercedes.

--
Ray O
(correct punctuation to reply)

j***@hotmail.com

2008-07-01 03:36:01 UTC

Sure, 99-01 or so have Shift Solenoid E and maybe other problems.
These aren't the best transmissions and that could be one of the
problems. The others are to make sure the engine is well tuned (for
example, valve clearances, timing belt, oxygen sensors, spark plugs --
use NGK Iridiums). 16MPG in all-city driving is OK, but if you can
only get 16 MPG with highway driving then it's really bad.

a***@att.net

2008-07-01 13:10:29 UTC