: My new 2009 STS is not doing well on gas



OrlandoO
04-15-11, 04:37 PM
I just bought a 2009 STS V8 (30K miles) last december, it is not doing very well on gas. It is doing an average of 17mpg. Is this the norm or I should expect more?
Thanks

HiYall
04-15-11, 05:11 PM
My Mom has a 08 STS with the North* and gets an avg of 18mpg tops. I have a 05 STS V6 and avg 22mpg. We have very short on ramps where I live and sometimes the traffic is moving along at 75-80mph...my 6cyl goes pretty well...however the North* seems quite a bit faster to me .....but does use a little more gas.

1BadCadSTS
04-15-11, 08:06 PM
05 STS4 1SG 14 mpg

EChas3
04-15-11, 09:57 PM
I just bought a 2009 STS V8 (30K miles) last december, it is doing an average of 17mpg. Is this the norm or I should expect more?

It should be a bit better in warmer weather but that's fairly typical for mixed driving. It is hard to stay under 2,000 RPM's for optimum mileage; not much fun, either. AWD is worse.

Different gas can help a little; as can occasional engine exercises (see sticky thread on the advantages of WOT!)

ddalder
04-15-11, 11:01 PM
Since I took delivery of my STS-4 AWD at the beginning of December, I've averaged 11.61 MPG with the Northstar. Kind of dismal, however with the winter months there has been a lot more idling. My highest has been 16.40 MPG while my worst has been 8.37 MPG.

rzambrano
04-15-11, 11:41 PM
I do 90% street and average 16.9 MPG. Best was around 20 MPG with 70/30 C/H. Worst was 15.4 with 100 C.

Frikiton
04-16-11, 04:46 AM
I'm getting 15-16mpg :( according to my AVG MPG I do a mix of city/highway .. I'm going to start using cruise control 55-60 when I hit the highways now, supposely anything above 60mph will use more gas.

onlyuscars
04-16-11, 08:18 AM
They are 2 ton Cadillacs, with over 300 HP in N* trim. I can get 22-23 loafing on the highway in the right lane, and going easy around town 13-15. All things considered that isn't bad, but this isn't the car for fuel economy.:confused: I have a mini clubman S for that,(my first non-us car) This is a Caddie!

Those numbers above require restraint

torogt
04-16-11, 09:21 AM
My 2006 STS4 1SG AWD gets 19.5 according to my average MPG computer on the car.

doowap57
04-16-11, 02:05 PM
Yes, That is what you should expect. I get 16 to 17 around town, depending
on how much I put my foot into it, and 24 + on the highway. I thought I got
26 before I changed out my rear tires for wider and stickier ones.
But I am happy with 24 +.
Enjoy your car, it is a Cadillac, building Luxury for a LONG time.
Remember the story about the gun, I would rather have one, and not need it,
than to not have one, and need it !
This also applies to the 320 HP engine.
Enjoy...:thumbsup::thumbsup:

P.S. Check your tire pressures monthly. I have those that indicate right
on the tire, red,green amber for, low pressure, OK, and getting low.

rzambrano
04-21-11, 08:55 PM
I took a short trip this week to Six Flags Magic Mountain and manage to average 27 MPG

STScaddyman65
04-24-11, 09:44 AM
My 06 STS4 averages me 23-24 mpg during my weekly drive of 100 miles per day, (all freeway). I drive 65 to 70 mph. I keep my tire pressure very close to 40 PSI and I use the K&N air filter. If my wife takes it around town too, it ends up at 21-22 mpg. I have found the slightly stiffer ride of the tires at 40PSI usually get me 3-5 more mpg so I keep them there. I have also found that you will normally lose about 1 PSI per month so you have to keep your eye on the TPM system. Remember that this is normally looked at "cold". I have the 3.6L engine too.

jordan00escalade
04-24-11, 10:31 AM
I'm not being a smartaz or anything but.. Has anyone ever used that little fan looking thing in their intake to increase MPG? I forget what they call it, but it's suppose to make the air flow better or something crazy like that and increase gas mileage. Obviously I've never tried it, I can't even remember what they called the thing. The commercial would come on late at night though and now I think they sell them at autopart stores. I hope someone knows what I'm talking about.

chazglenn3
04-24-11, 11:36 AM
It's called "The Tornado" and is total B.S. Don't waste your time or money.

rzambrano
04-24-11, 01:43 PM
My 06 STS4 averages me 23-24 mpg during my weekly drive of 100 miles per day, (all freeway). I drive 65 to 70 mph. I keep my tire pressure very close to 40 PSI and I use the K&N air filter. If my wife takes it around town too, it ends up at 21-22 mpg. I have found the slightly stiffer ride of the tires at 40PSI usually get me 3-5 more mpg so I keep them there. I have also found that you will normally lose about 1 PSI per month so you have to keep your eye on the TPM system. Remember that this is normally looked at "cold". I have the 3.6L engine too.

40 PSI, wow! Correct me if I am wrong, but recommended tire pressure is 31 PSI. I think your putting safety behind increases gas mileage. Over inflated tires, might increase MPG, but decrease handling and are more prone to damage and faster wear. I think the cost of replacing a tire due to faster wear does not offset the increase in MPG savings.

EChas3
04-24-11, 10:31 PM
My 06 STS4 averages me 23-24 mpg during my weekly drive of 100 miles per day, (all freeway). I drive 65 to 70 mph. I keep my tire pressure very close to 40 PSI and I use the K&N air filter. If my wife takes it around town too, it ends up at 21-22 mpg. I have found the slightly stiffer ride of the tires at 40PSI usually get me 3-5 more mpg so I keep them there. I have also found that you will normally lose about 1 PSI per month so you have to keep your eye on the TPM system. Remember that this is normally looked at "cold". I have the 3.6L engine too.

Bouncy-bouncy, uncomfortable, dangerous and likely to cause undue middle-tread wear. But if it makes you happy...

kmf1031
04-29-11, 08:07 PM
Originally Posted by STScaddyman65
My 06 STS4 averages me 23-24 mpg during my weekly drive of 100 miles per day, (all freeway). I drive 65 to 70 mph. I keep my tire pressure very close to 40 PSI and I use the K&N air filter. If my wife takes it around town too, it ends up at 21-22 mpg. I have found the slightly stiffer ride of the tires at 40PSI usually get me 3-5 more mpg so I keep them there. I have also found that you will normally lose about 1 PSI per month so you have to keep your eye on the TPM system. Remember that this is normally looked at "cold". I have the 3.6L engine too.


OMGosh 40 PSI is just going to have you shopping for new tires way too often. The recommended cold tire pressure is 30 PSI for my 07 STS V8. Have you looked into getting "low rolling restistance tires" instead. They are supposed to get some increased gas mileage but heck folks I bought this car for its nicely balanced performance and luxury, for me slightly higher emphasis on perfromance.