guod

iTrader: (2)

I have been trying to figure out what is causing my horrible gas mileage in my sc400. I have been driving the car lightly, do not use the pwr button and rarely use the overdrive button as i let the car choose when to shift. I have been getting close to 260 miles on a tank while putting in 17-18 gallons. This is about 14-15 mpg. What could be causing this all of a sudden? I changed my steering rack bushings, got an alignment, oil change, diff oil change, atf change, daizen sway bars, 18" is350 wheels and I use the air conditioning all the time. From what I have read I should get at least 300 miles out of the tank as that seems to be a pretty common result..

any ideas?

Homeless

Really man, you don't use the overdrive button and you are wondering why you are getting bad gas mileage. The overdrive drops down the rpm's while crusing so you get better gas mileage might want to try that for starters.

guod

iTrader: (2)

i meant i did not disengage overdrive. i let the car do all the shifting. i know what overdrive does..

Homeless

Sorry misunderstood.

2700$oarer

its your ac... anything else?

guod

iTrader: (2)

Would it reAlly make a huge difference in terms of Mgp? That would be close to 3-4mpg

GRN MNSTR

yeah, the only thing in that equation that sticks out would be the AC but I imagine it wouldn't be that big of a decrease in mpg...lucky for me I never use the ac i prefer driving with the windows down...I only use it when it rains lol

RedPhoenix

iTrader: (10)

When was the last time basic maintenance was done?

Fuel Filter, Plugs, Wires, Coils, Cap/Rotor?

nfordhk

iTrader: (2)

Driving with windows down is the same as driving with AC until around 55 mph where its more efficient to use AC to get better gas millage.

masagsxr

yep.. could be the use of your A/C and depends what your tire setup is. Wider tire = less gas mileage..... What does your car says on the digital odo (avg. MPG)? Is the 260 miles when the gas light comes on? Mine comes on about 300 miles. Maybe a little over

over40driv

Sounds like you need a good tune-up and fuel filter.

guod

iTrader: (2)

do not have a digital readout since I have a 1995.

As far as plugs and wires, previous owner replaced them not too long ago. not sure about the cap. fuel filter, have no idea.

guod

iTrader: (2)

BUmp...still looking for info. I have 190 miles on this tank with less than a quarter left

kevro

iTrader: (2)

my sc3 got similar gas mileage to you, the ac is not causing it, my new car (330ci) has detailed information from the cpu telling me about my mileage. I do 60 miles a day mostly highway and if I do it with windows down thru a whole tank I avg 22.3 mpg, if I do it with windows up and ac on the whole time I avg 26.2 mpg, I didnt think this was possible until I ran my own tests..my sc is now 1jz swapped and I rarely drive it so I havent figured out my mileage yet, I have to think there was something wrong with my sc getting that bad of mileage, this was further evidenced when i failed emissions MISERABLY.... gl with the search.

p.s. fueleconomy.gov says sc400 should get combined mpg of 18, that site is usually pretty accurate.

agridi

Have the Oxygen sensors checked.