09 Cobalt with bad gas milage!!!! HELP!

[chevrolet25]

Ok so i bought this car almost a year ago and slowly noticed a decline in gas milage. I have never got past 30 mpg and i have a 2009 LT2 sedan with 2.2., it has ss 17" mag wheels with the stock pirelli tires. Its not turbocharged or supercharged and completely stock!!! i recently bough and K&N cold air for it to see if it would help and nothing! now i recently had it in the shop for a knock in the suspension and after several times in the shop, now its getting worse!!! now mind you, i drive ALLLLLLLLL highway 50 miles a day at 65 and im lucky to pull 26mpg, im averaging 24 right now. Im lucky to get 250 miles on a tank and if i do, its burried in the RED! it has fresh oil in it now and is always on time for service. Tire pressure is good and 09 models have the fuel filter inter-graded in the fuel pump, so i cant change that. I checked the plugs and i thought they looked fine. no carbon build up and smelled like they were burning clean! i have ran probably 5 quarts of fuel system clean out and injecter cleaner GM BRAND!!! i always run chevron fuel! o and heres the kicker!... If i run premium fuel, i get worse milage!! WTF please help me guys any inpute i will consider i cant afford to pay 95 bucks an hour for a shop to diagnose the problem! im thinking they did something when they had the suspension tore apart, but it does not pull so i would assume the alignment on.... thanks

---------- Post added at 01:07 PM ---------- Previous post was at 12:56 PM ----------

o yeah and the car just rolled over to 40,000 miles

 

[reyesa21]

i hav the same exact yr lt model. and i get bout the same. i dont know if it is what its supposed to get our not but yea i dnt like it. mayb its jus sedans but i kno tuning it will help. i hav yet to tune mine but i will soon

 

[chevrolet25]

well that makes me feel a lil better and that your getting sh***y milage too! lol jk but yeah i donk know. Someone told me that it could be that my model is fully loaded with every option puts on some weight and it being sedan compared to the base LS's they get the so called epa reading from........
And aww you have black!!! i wanted black so bad but all they had was white in that trim

 

[sfwg]

get a tune problem solved...i get 360 mi off of a tank=30mpg trifecta tune ftw(that tune was just to get more power, remove throttle delay,get rid of govnor)

 

[cobalt123]

tune it your problem is the premium fuel. the stock 2.2s are not flashed to use octane higher than 87. tune it for the higher octane or go back to 87.

 

[reyesa21]

how do you tune it? is it tht lil device ur plug in?

 

[chevrolet25]

i dont use premium fuel all the time, i tried it just that once to see if it would improve my milage, and obviously didnt.........

 

[cobalt123]

how do you tune it? is it tht lil device ur plug in?

tune it using a trifecta tune...it plugs into the obdII data port

 

[chevrolet25]

So how do i get my hands on one of these trifecta tune devices?

 

[Intmd83r]

how much is the tune thing ? right now im at 11mph avg speed and getting 18mpg lol

 

[Spacey_stacey75]

Yes more info on this please........

 

[fdfstoscvy]

I went through all of this the first year with my 09 LT and had it back to the dealer many times for I was getting between 13 to 16 mpg. I was told that due to there is ethonal in most gasoline that is the problem.
I was told to use gas from golf that has no ethonal and you will see the mpg go up but not by much. I get now around 18mpg but this is backroads and highway with hills. I can get 24 with a good wind behind me.

 

[Intmd83r]

my 05 if i do highway i can get 28mph think avg speed is around 35mph

 

[chevrolet25]

see this is really starting to piss me off!!! i have gone through this entire car trying to resolve the problem and have yet to have any luck!!! I have tried EVERY GAS around me! ethonal free gas, shell, chevron Premium and 87oct. Fuel additives and nothing!! what really pisses me off is i traded my Mint condition 97 cavalier with 70k on it for this fu***** car and i was getting 28+ in the cavalier, with my foot in it! Now this brand new car is getting damn near 21 in the city and 24 on cruise control! WTF is everyone getting this???........... And is a tune guaranteed to increase my milage 30mpg+? i dont want to drive 500 miles to get it done then drop 300/400 bucks on top of it! so has anyone had dramatic increase in fuel milage with the trifecta tune?

 

[RedDead]

u could try this lol j/p that shit sucks man

 

[chevrolet25]

ha ha yeah at this poin i feel like doing that! shit! i should have kept the good ol' cavi! someone please make me change my mind about selling my new cobalt!

 

[726.0chevelle]

Yea it doesnt make any sense my car is an 07 auto with 86k miles factory plugs only changed the fuel filter only once. All I fill up with is the 10% ethanol gas and i average 29 to 30 driving pretty fast (3 tickets one year fast) Did you put a cold air intake on it or something maybe a k&n oiled filter might be messing with your maf meter. Id bring it somewhere if you cant figure it out soon cause you might be runnin rich and that could screw some stuff up over time.

 

[chevrolet25]

well i put the k&N on after the fact, i thought it would improve the milage but it didnt! And the dealers just tell me they cant really do much with out a light being on......

 

[YelloEye]

When I got my tune like 3 years ago on my 2.2 I had to drive back to TN with it, avg mpg was 38+. Trifecta tune is worth it, so long as you don't drive it like you stole it you will notice an increase in your mileage. Around town driving like an ass I was getting 23mpg, thats flooring it from stoplights and generally doing really stupid things lol. Hell even at the drag strip after driving around town my average didnt drop below 21.

Vince can dyno tune you remotely, you dont have to drive over here to WA to get it done.

 

[chevrolet25]

ok so before thd tune what were you getting for milage? i seriously thinking about gettin this done. Anyone from the west coast, what shop do you recomend? Salt lake utah or seattle washington. i just dont understand why my milage keeps droping could that be from just gettn out of tune over time?

---------- Post added at 10:06 AM ---------- Previous post was at 09:48 AM ----------

off a full tank of gas, if i drive 25 miles on the FREEWAY on Cruise my needle on the gas guage will move up one line!