abounly

iTrader: (27)

So your saying you're getting around 550+ full tank? 100% highway?


I agree, bet even if you floor the 300 it won't go anywhere might as well baby it. 400/430 is so much more fun to drive.

yelnoc

I get as high as 26.5 on straight highway and never less than 20 combined 50/50 highway and city on my 03 430, but that is pretty easy driving which makes a difference.

350TPI

Well it WAS 21.5 mpg but since i changed the plugs from the oem denso's to ngk laser plats it has fallen to 18.5 mpgs.I should have been patient and just ordered from rockauto instead or getting the best i could find here in town....

1QWKGS4

iTrader: (3)

I also get this with similar driving..

abounly

iTrader: (27)

Yeah I'm about the same as well

raytseng

Are you saying you got spark plugs that weren't the right application?
Or that you got new spark plugs that were the right application but just not OEM recommended?

In other words, exactly what plug partnumber did you get, and what were you looking for?

Half of our cars may randomly come with ngks, and it's also an alternate part in the Lexus manual itself, so that by itself doesn't mean it's a bad plug.

chubz

iTrader: (1)

i just took my gs 300 on a little trip from new jersey into p.a (1.5hr drive) to visit my father in-law and i averaged about 26.5 hwy mpg. i used alittle over a quarter tank.

chicov8

im getting 15-16 mpg from short city drives to 20-25mpg on higway (02 gs430)

350TPI

They were the right application but not the OEM recommended.I am not saying its a bad plug but its all that i have changed.The mpg drop coincided with the spark plug change.BTW,it was the laser platinum BKR6EP11.I just cleaned the MAF and if gas mileage doesnt increase i will go with the denso iridiums.

JAYGS4NYC

My 02 GS430 gets great gas mileage. 80/20 hwy/city 21.5mpg w my 20s on. 16.5 around town and 26.5 all hwy. From what ive seen the GS3 is about the same bc u gotta get on it more. My 98 ES300 DD does a lil better but nothn drastic. My sold 98 GS400 also did about the same as the 430. I do alot of hwy driving maybe higher than 80%. Either way these cars IMO are great on gas.

repugnante

If you have the 400, this is a downgrade

350TPI

Yeah,i do.I didnt think it would make much of a difference but it did.I will get the the OEM densos.

repugnante

^ yea, make sure you get the Denso Iridiums