my mileage has been up and down depending what im running,and how im driving.. but lately, consistantly(driving with a feather foot mind you) ive only been getting 16-19mpg, no lie! ive been running a lil rich too, but only every once and a while, mainly the first 15min after start up. ive got no lights on, and all my hoses are nice n' tight. if anyone has any guesses or suggestions, id much appreciate, thanx!

 

could be a lot of things that can cause this. need more details. mods? recent maintenance?

 

currently mod free. have had past work but no problems after uninstalled(this is all atleast 6months ago.) i had a Greddy turbo, and unknown header put in at my uncles shop. got rid of it all because i wasnt diggin it for a daily driver.

the gas issues are very recent. they all started monthes after everything was uninstalled. i noticed tho that my gas mileage has never been the same since i broke my camshaft position actuator while changing my belts.

and for maintenance, i just changed my spark plugs,engine oil, transmission oil and ditched the CAI last month to see if my mileage would improve, but it didnt.

 

What kind of wheels/tires do you have ? Tire pressure ?

How are you with oil changes ?

Do you have an automatic ?

 

ive got an auto, my oils been changed in the last 1k miles, and im rollin in steelies with costco treads(forgot the type, id have 2 check) and i just put air in my tires.

 

I have heard may xA owners who have Automatics say they have issues with their MPG (lower then average... average being say 35-37 mpg).

Its partially due to the added weight of the auto transmission, plus as "smart" as the computer is to know when to shift(the optimal time) , a human brain who has had 1000's of miles of experience under their belt driving a manual can/ and does out perform a computer every time

 

true true. everyone say sticks get worse gas mileage but from experience (when im driving with mpg in mind) it seems better.

and i hope your just guesstimating with that average cuz even with some recent tunes ive done im no where near those numbers, nor have i ever been. except maybe when i first got this car, and even then it was bout 27-29mpg in the summer.

 

Prior to hitting 100K Miles on my 06 xa, i can get 39 MPG with new oil change 33 psi on tires.

I have 138K all hwy miles and drive about 5 over speed limit. I avg about 35 mpg.

Mod free. you may have a valve prob.

 

either a valve problem or you need a new Cat, or O2 sensors with really crazy readings that aren't triggering the check engine light... get any surgery lately? lead foot? went from highway to city driving?

I changed from highway miles in CT (getting around 32-with all the mods) went to start driving in Ca, L.A. with city traffic (19mpg with all the mods).

~my suggestion take it in to the dlr and advise them of this. If you can't get an answer from them call the Scion Customer Experience line and they can help you look into the concern with the dlr.

 

i have been doing a lil more city driving than usual but i wouldn't expect to loose 10mpg from it, its not that much more than before.

and i was gunna bring it into the shop couple weeks ago when it all started but my warranty has been up for some time now and the money i do got is goin towards some new spacers,rims, and new treads. thats why im checkin here first.

i just checked my valves the other day and there good, i didnt think bout the Cat or the O2 sensors yet tho. i guess ill do that next, Thanx for all the advise!

 

The only way I could see a 1.5l 4banger get 15 mpg is if someone punched a hole in your fuel tank.
Seriously, you might have a valve problem. But no matter how much damage, if the engine sounds normal and runs normal, just the mpg has gone to hell, then it boggles my mind. I've honestly never heard of that happening. You might want to poke your nose around a scion dealership and ask for opinions and if they've ever heard of it.

 

dooode im just as baffled as you are! ive been doing that periodically when i go by pepboys, and the scion dealer down the road from me. but nobody has any good opinions or even guesses. just the valves, and there fine!

 

valves would be singing, honestly. Check your voltage to the O2 sensor. Might be off. If so, try replacing with an OE sensor. That might take care of it.

Are you having any abnormal problems? Maybe lights are flickering or something like that?

 

my headlights flicker a lil bit when i first turn on the car, like the first 5min. then it stops. and about the O2 sensor, u think not running an OEM sensor would cause a problem like this?

i love this car, its reliable and fun(most the time) but im gettin to the point where i should just throw it on craigslist and get what i can out of it and get a new ride. id hate to tho. i figured this would happen ever since i first started going aftermarket and tuning it out, the problems came slowly then just began piling up. undid all my mods after gettin tired of having to spend every weekend tuning and still left with problems!( if ive learned one thing its next time i start modding a car, its definitely not gunna be my daily. gunna keep it to the weekend driver.)

 

yeah. aftermarket o2 sensors are generally crap.

Another thing you could try is what I do about 3 times a year. Unplug your battery, overnight. In the morning plug the cables back up and start the car. DO NOT touch the gas. Let it run for about 30 minutes at idol. Turn car off, then back on and take it for a drive. If it's the ECU after all the tuning then it would reset to your driving style.

Since resetting the ecu is free try that first.

 

alright, thanx!

 

any update to this? I am having similar problems..
thanks

 

Damn, zombie thread from the dead! Almost 2 years ago...

My mileage is back to avg. About 29-35. But I've Done a handful of things since I had the gas Mileage problem that would effect it. I've replaced my o2 senders, put a Cai back in, dropped it 2in, put some iridium tip sparkers in, and replaced the whole valvetrain n head(had some issues after beat the hell out of the engine for 190k miles). But back on point, any of those changes could of helped my mileage, wish I could point something spacific out that would help but I never payed attention to how each mod effected my mileage.

Excuse any bad grammer or mistypes, I typed all that on my phone