scuba821

How come the IS300 can only get like 16- 19 mpg? There are other cars with bigger 6's and alot more hp, that get like 23-26 mpg.

I searched around to see if anyone had talked about upgrading spark plugs but found nothing, so........now I am gonna throw it out here.

Have any of you upgraded your plugs? Did it help? And if you haven't, do you think that it would?


Let me know your thoughts......thanks

lisnup65

The IS300 was very poorly designed when it comes to fuel mileage. I am only averageing around 14 to 16 in the city. The gearing may make the car silky smooth, but at the expense of major fuel usage. A 3.0L engine is not that big and to use almost the same amounts of fuel in a 3liter to move the IS as a 5.8L to move a full size pick-up is ridiculous to say the least. Hiway cruising should no require the motor to run at 3K RPM's. Hiway cruising should be around 1500 to 1900 RPM's and the lack of a proper Overdrive gear is just very poor engineering on the part of the Toyota/Lexus. I cant see any benefit to changing the plugs!!! I have yet to see a fuel improvement from plug to plug. I tried the split-fires once and I lost mileage in my former Grand Prix.

TNguyenIS300

[QUOTE]Originally posted by scuba821
[B]How come the IS300 can only get like 16- 19 mpg?

Not true for my IS300 ----> My average MPG is 22.5 for (60%) highway (70-80 mph) and (40%) local driving (35-45mph). Plus, I only have less than 1500 miles on my car (I don't know if it gonna make any different)

I guest you must of driven really hard and power button on most of the time in order to get 16-19 mpg.

GMoney

Yeah, the gearing is very similiar to a car with a 4 cylinder motor. 60 MPH and 3000 RPM is kinda high. My old VW did the same thing and it had a V6 in it.

They should have integrated an overdrive gear...but oh well, We all knew the gas mileage sucked when we bought the car...so guess you just gotta learn to deal with it...sorry....thats the price you gotta pay for owning an IS

vlad_a

As far as I know, IS300 has an overrdrive gear - 5.
4th is the direct 1:1 ratio.
The 3K rpm on highway was done on purpose so the car would have a better response.
It's a sports car, not a cruiser.
Of course, I would prefer to have 6Spd manual to have the 6th gear for cruising.
Well, when you spend close to 40K (in my case) on a car, you should be able to afford poor gas mileage.
I knew what I was getting into when I bought the car.

I was getting 22-24 MPG on long trips (80-90MPH). That is with SRT intake, which increases gas mileage.

Izzy300

I just filled up with my first own tank of gas. (This is after the dealer filling it up when I bought it.) Talk about good timing, gas is so cheap right now! Filled up with premium at 1.31 per gallon at a Texaco. I saw a station that had regular unleaded for 1.12, the only thing that has made me miss my civic so far. I could fill that sucker up with $10, the IS cost me about $19 to fill up. I calculated my milage and got 19mpg for that last tank, which I don't think is too bad.

IS300Man

dam, $1.31 for premium, lucky, i pay like $1.89

soulstalker

I would not recommend replacing the spark plugs.

The IS300 already comes equipped with probably the best spark plugs currently available -- the Iridium type.

If you went out and priced these things, they run about $20-30 each spark plug.

SeattleSheila

The cheapest Chevron around here has premium for $1.77...

glex

wow !lucky the gas in Cali 2.30 a gallon.

scoot557

Damnnnnnn - right now premium(93 octane) is 1.84/gallon - im movin to Oklahoma!!

SeattleSheila

Scoot, you do not want to live in OK. Believe me.

Izzy300

Yeah don't move here, unless you're one of those people who stay at home all the time and never do anything except see movies. THere's NOTHING to do around here. At least cost of living is cheap, I can realistically buy a nice new house here for ~$150000 as opposed to other places. If you want cheap gas, move to Texas...

BTW, I was driving around and passed a different Texaco where premium was $1.27 and regular was $1.10!

SeattleSheila

Geeze Louise...the Texaco stations up here are the most expensive of all of them.

dpatterson069

hey everyone...
what do you get to a tank in your IS300's????
when i first got my car, i was getting about 210-220 miles a tank!!! WITH NO HARD DRIVING!!!
now, i can get around 240-250 with some occasional hard driving...both these are FULL fill ups!!! (start of empty light)..

on the freeway at 70 mph, the car is at 3000 rpm..
my mom freaked out on me saying that i drive like a maniac to use all that gas(1 fill up a week)
i tell her to calm down cuz the IS300 is a bad fuel efficient car...

man, mom's can be tough...