RocketGuy3

iTrader: (1)

12 mpg is unacceptable for a modern 300-hp car running on premium fuel, and in my experience, it is definitely abnormal in the IS. So he has a legitimate complaint... unless he really is just driving it a mile or two to and from work every day, in ice cold weather, and romping it from stoplight to stoplight.

I'm not sure what the point is of your S2K example, either. You got just three fewer mpg and used it on the track. That's pretty normal.

Recluse

I have posted about this numerous times already....I drive 99.99% city, and I get about 13 MPG. I have always gotten that since the car was new (I have 3500 miles now)

My last car (BMW Z3 Coupe) got similar MPG under the same conditions, so I can only assume that what I am experiencing is normal for a car driven at an average of 12 MPH in second gear for 11 miles total (round trip) each day, along a path with 50+ stoplights, and accelerating from a stop at 1200-1500 RPM, with shifts at 4000 RPM or less.

But if you find a way to Lemon your car for MPG, let me know.

iKenn

iTrader: (1)

What happens if they declare your car a lemon(or lime depending on which way you roll.) haha

slowandlow

i am bringing it in today for the 3rd try and the rpm never drop below 1200 rpm even if the car has ran for a hour. 250 awd
on the window sticker it staits thait the car shall get between 18 and 26 mpg city and 23-33 highway. my normal driveing when i was getting 18 mpg i would go WOT a few times. after problem 12 mpg i tryed babying the car never going over 2500 rpm and was olny able to get 15 mpg on the tank.
on my florda trip i had a average speed of 70mph and got from 28-30 mpg. the last trip after idleing problem with a average speed of 70mph i got 24mpg

slowandlow

my aunt had a car declared a lemmon she got a new car but went from a crystler to a dodge. her boot for the top would never stay on and got the car lemmoned for it.she lost 4 of them on the freeway. i think i will get the 350 maybe it is a better engine than the 250. i am not sure

sirkfc

check your tires?

19psi

1. you will never get the car bought back because it gets poor mileage. it has to be a major problem that can be found by the dealer that occurs several times within a specific timeframe and cannot be repaired ina reasonable amount of time.

2. don't believe what the sticker says about mpg. the epa tests cars in a specific manner, which do not mirror typical driving conditions.

3.the winter fuel formulation lowers gas mileage, this could be the cause of your drop.

4TehNguyen

iTrader: (1)

i drive full city and get 21.5 mpg on a 350

1200 rpm even after the car was on for an hour, that is a problem

Joeb427

iTrader: (1)

Maybe the OP is using regular gas too.

Bass Mech

you might ask them to swap out the 02 sensor sounds like its running too rich. also there may be somthing wrong with the temp sensor, what your describing sounds like the ecu thinks the engine never warms up. when its cold the ecu will run the engine rich the same way a carb will use a choke. that would explain both problems.

19psi

you are right however; considering the obdII nature of the car, the ecu will detect a fault wtih either of those circuits and illuminate the cel within a couple drive cycles.

he could however, have a vacuum leak, unlikely in such a close to new vehicle, but that would cuase a high idle as the ecu is trying to adjust fuel trims to meet the target a/f map. the cel won't turn on immediately until fuel trims are at the maximum allowable range.

Big Willy

Not sure how the lemon laws work, but I'm sure you'll have issues if your looking at them replacing the car for poor MPG.
The real issue is why are you only getting 12-14, that's where the actual prolem is.
The high idel is pretty normal for cold weather.

slowandlow

well i just got my car back. had a real complaint about my adviser for takeing in the car. he got a repromand or sothing. well he was reported for his behavor and now i am back to the lady that works with my mother. now they drove the car 100 miles in city and highway and got a 25 mpg average. with i bet they drove 60 on the freeway and drove like mis dasy in the city. after i got the car back the weather warmed up and the idle was fine but as soon as it got cold the idle takes a long time to drop to 800 rpm.

i drive 10 miles each way to work.
i got him to admit this is not normal but they cant find a problem.

in my olds alero i get 18 mpg year round with a 3.4l v6 with 190 hp and 200t and it is a 2001.

i still have a leaking winshild washer fluid.


any advice will be greatley welcomed.

i think it is a air intake censor if the car has one. or the tps or mas air flow and last but not least a o2 . sending false readings but the readings dont look false to the teck

19psi

driving 10 miles one way doesnt' get your car hot enough to achieve maximum mpg. cars take a while to reach operating temp. especialy when it's cold out. the ecu runs the engine richer when it's cold and the engine isn't at operating temp. that's why your mpg is lower. you probably reach full operating temp for the last 2 miles of your drive.
if the sensor readings were out of range, the check engine light would be on.

4TehNguyen

iTrader: (1)

how long does it take you to do that 10 mile trip