Just thought I would mention this. I replaced the air filter with the K & N replacement filter. My avg. mileage has increased from 14.7 to 16.9.

Not bad for 39.90

 

Interesting observation Randy. Would appreciate an update in a week or so to see if that holds true...I'm getting around the same 14.8 you are at, and with gas at $3.50/gallon every llitlle bit helps.

 

My last tank of gas resulted in 18.6mpg calculated by hand in my 2003 GX. The computer read 19.6, but a manual calculation was a little lower than the computer. I used medium grade Shell gasoline and my commute is 45 miles round trip, of which 40 is highway and 5 is city. The elevation changes up and down several times spanning a range of 800 feet during the commute. I am using the stock air filter.

I normally set my computer to display the Instant MPG so I can tailor my driving habits to net the best fuel economy. I get better economy with manual control than I do with cruise control because I slow down 5mph below the speed limit when climbing hills (cruise control always wants to keep a constant speed and works harder going up hill). I just let it coast going down hill with a light throttle if necessary, going up to 5mph over the speed limit. This is a 10mph range (speed limit +/- 5mpg) which is wider range than the cruise control uses, so I'm able to get better economy manually. I'm sure I would probably get better fuel economy in a flatter part of the country.

I definitely notice the best fuel economy with premium fuel, but after doing the math the MPG gain is not worth the price over standard unleaded (I don't get enough extra miles out of the tank for the money by paying for premium). However, I still use medium grade most of the time, with a tank of premium mixed in every 3rd or 4th fill-up.

I am interested to hear about your fuel economy numbers after a few more tanks to see what your new norm is. Curious, what grade of fuel did you use?

 

i always get premium for my baby. My avg mpg is 16.9 and i never changed any filters or anything (well except for the oil one). But yeah it definately would be nice to know if avg mpg can be increased

 

Those of you getting the 14.x MPG - do you drive city streets for freeway. I am still breaking my '05 in (only 4500 miles thus far) and I am getting a solid 14.6 MPG (my calc, not the GX). I only drive city and have very easy 3.5 mile commute (so the engine barely warms up). I expected that type of mileage and am actually pleased it isn't worse. Just wondering what I might expect on a longer freeway drive.

And I too, would be interested in hearing if the K&N continues to deliver better MPG over the next few tanks. Thanks for posting that.

 

My average MPG is a little over 17 (17.2 to be exact). This is a mix of "light" city driving and highway miles. By light, I mean that less than 20 minutes any one time and little or no stop and go traffic with most speeds between 25 and 55 MPH. NOTE: If you use anything other than regular fuel your miles per gallon will suffer. If your getting less than 17MPG in similar circumstances and using premium fuel, it's your own fault. Try changing to regular and see if you milage isn't similar to mine.

 

I use mid grade fuel and average 18.9 miles/gallon, calculated by hand. The computer was a bit over @ 19.4 mpg. This is with heavy driving 80% highway, 20% city.

 

I also have a K&N. My husband swears by them and has one in his Toyota truck and Z06 vet. In the city if I am not in a huge hurry I have gotten up to 18 before, but the avg is high16's low 17's and I have gotten up to 21-22 on the highway. This changes every week, it all depends on how windy it is, if I am using my air, if the windows are down and if I am in hard core traffic. I am usually in a hurry every morning in Atlanta traffic I am always using every inch of my v-8 to get me to my desination.

I think the K&N was around $80, but it will never have to be replaced again...

 

I got an average of 14.7 mpg on city driving. With my last trip to Vegas (95% freeway driving) it clocked at 17.8 mpg. The 14.7 is based on the first 12,000 miles of driving on my 2003 GX470. Right now, I'm checking on my tire pressure more often hoping to improve the gas mileage. Hope this helps.

GSX4

 

Tank 2 and holding in the high 16s. Regular fuel, 50/50 mix hwy, city

80 bux for the K+N??????? That's a hose job. Double the price.

 

I dont know if it was $80 for mine, but one of them that we bought was $80, I think it might have been for the vet? Like I said, we have 3 of them, one in each vehicle.

 

I went looking for a K&N for my 2005 - nothing shows up. Does anyone know if they changed the filter in the '05 when the horsepower increased?

Thanks

 

Did you go online to K&N? Did you checks Jegs online?

 

Looked both places, Googled a few other shops and they all came up with the same thing, just the oil filter for a 2005. They list the air filter for a 2004, but nothing for the 2005. I sent K&N a request for a P/N.

I am taking it in for service tomorrow, I will check if the Lexus parts for the 2 different years are the same.

 

You can use the sequia air filter, its the same part number as the gx. Truckperformance.com