I have an 02 sunfire - 2.2L Eco, I used to get about 360miles per tank, car is still running fine, but only getting about 260 miles per tank, only 42000 miles on car.

Any help would be great

you may want to check out the sticky at the top about gas mileage

anyway

what oil are you using
make sure your tires are properly inflated
change air filter if you havent already
are you running the ac anymore then you use to?
also try to dump a can of seafoam in your next fill up or techron fuel system cleaner
i get close to 400mi on my 96 automatic

just to add, not sure how true it is, someone at a dealer told me it was recommended to change your fuel filter every 15K-20K miles?

Also, fuel with ethanol will deliver less mpg. What is in your fuel?

I've tried a new fuel filter and it made no differance what so ever. Generally I just fill up with regular gas, I've tried premium for several tanks and that also made no differance.
I was also on a long trip last month, all highway driving, thought for sure I'd see an increase, but nothing.

Does anyone know what the rpm's should be when crusing at say 120km/h (75mp/h)?


Thanks....

premium will have no positive affects on our car if anything it will be negative its a waste of money. what do yoiu mean what rpm at 75.. you should be steady on the gas n go a constant 75 in your highest gear. did you check your tire pressure? drive down the freeway with the windows up it creates less drag. Again what oil are you using? heavy oil will decrese mpg, The biggest gas saver is your foot. Take off slowly. When you start from a stop thats when you waste most of your gas. Also Change your airfilter and clean your throttle boddy with carb cleaner it can get alot of junk in there, carbon buildup etc

I'm using 5w30 oil, yes I've checked my tire pressure, and I've also tried driving like a sane person for several tanks of gas, with no effect.

What I meant by rpm at 75 was that what should my cars rpm's be at when I'm doing 60 miles an hour, or 75 miles an hour. I'm trying to get a reference point to compare to mine. I'm being to wonder if I'm having problems with the overdrive, as long highway driving trips make no difference with the mileage. I don't remember what the rpm's were at 120km/h - but I don't recall it being 3200-300 rpm.

Thanks

im completly lost overdrive on a cavalier?.. you should be at around 2800-3000 at 75mph i think? your airfilter and throttle body is a BIG part of gas have you cleaned/changed filter?

My Cavi runs 3000rpm@80mph.

2.4L / 4 spd auto

Hope that helps

Those platinum plugs (100,000 miles) really don't
work all too well about mid-way during their life.

The gap widens....flame-out can happen at high speeds.

Give them a re-gap, it won't cost anything but some time.

or just buy new ones there not incrediably expensive

I set the cruise at 75mph yesterday coming home from work, and the rpm's were at about 3250, today same thing, cruise at 75mph and the rpm was at about 2800.

^^ weird were you going up any kind of incline how long as it at 3250?

No, flat highway, as for long, if you mean how long it was at 3250rpm, the whole way home, about 15 miles

Run you car on a free diagnostic...Sounds like you need a 02 Sensor...

CavOnBags (1CAV2NV) wrote:Run you car on a free diagnostic...Sounds like you need a 02 Sensor...

wtf???

75mph this morning on the way to work - about 3200rpm
80mph this afternnon coming home from work - about 2900rpm

ok well how far is the freeway from your house? it sounds like the car isnt really warming up enough. It seems that the freeway is somewhat close to your house? try to let it warm up a couple minutes before you leave.

my gas mileage has suck for the past 3 years.
I get 16-18mpg city and 26-28mpg highway. I have bolt on mods done to my car. It is really starting to tick me off. I have changed
-fuel filter
-both O2 sensors
-IAT
-Spark plugs to the one step colder
-Coil packs bought new wireing for the ignition
-used fuel cleaners
-just got a new engine.


Only thing i have not changed is the ignition control module.




2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
"You can please some of the people some of the time but you can't please all the people'
all the time

Found an iginition control module only thing i have not replace in my engine yet ignition wise.


2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
"You can please some of the people some of the time but you can't please all the people'
all the time

^^you might try 5-30 synthetic oil, clean or replace your air filter, pump your tires up to the max psi, and you should not have one step cooler on your spark plugs unless you are detonating. What temperature does your engine run at? You can get better gas mileage but with a little loss in power by increasing the operating temperature.

One other suggestion is to downshift always. As I understand it, if you are not on the gas and you are over a certain rpm, such as when downshifting or going down a hill, your injectors shut off and you use no gas.

Last but not least, if your tires are out of alignment you could be causing more rolling resistance. If they are not wearing unevenly you probably do not have to worry about this. What did you do differently 3 years ago?


02 LS Sport http://www.cardomain.com/ride/2135396
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using synthetic 10W30 now. I use 5W30 but they did not have any.

Replaced filter, tires check once a week, other thing is i do real short drive work is about 2 miles away.

I drive like a granny because i have my daughter with me so i granny shift etc.. no fast driving. Car aligned every 6 months


2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
"You can please some of the people some of the time but you can't please all the people'
all the time

do an engine flush and run slick 50 next time you do an oil change. It may not be your problem but its worth a try. I have gotten about an extra 10 miles per gallon after switching to pure syn and oil additive

Brad M wrote:do an engine flush and run slick 50 next time you do an oil change. It may not be your problem but its worth a try. I have gotten about an extra 10 miles per gallon after switching to pure syn and oil additive

i would @!#$ myself in utter glee if i got another 10mpg out of my car on a regular basis

imagine a z getting 38-40 mpg, not on a long highway trip..................

I replace with one step colder because the stock ones were white so i went with one step colder. They are the AC delco plugs for the GM supercharger.


2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
"You can please some of the people some of the time but you can't please all the people'
all the time