Last post on May 01, 2013 at 12:42 PM
You are in the Cadillac CTS/CTS-V
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Cadillac CTS, Cadillac CTS-V, Sedan
#130 of 266 Re: 2009 CTS poor mpg [blackcadillac]
Feb 23, 2009 (9:26 pm)
Both of my 2004 + 2007 CTS did improve highway MPG by about 2 MPG after
about 5,000 miles. I don't see any way for merely breaking in to increase around 10 mpg.
If your commute has lights and stop and go, the avg mpg means very little.
The highway run on instant means more right now and may be your best way to convince your service there is a problem. The sluggish running also sounds like a sign something is wrong.
I am not a mechanic. I just observe my Cadillacs using the instant mpg and only monitor average for longer highway trips. I have had several Eldorados with the 300hp Northstar, that all could get 25mpg highway at long distance or using the
instant mpg monitor at highway speeds.
A long shot wild guess is to check your oil level, in case they forgot to fill it up, although if seriously low, the car should warn you. Also make sure the tires are inflated where they should be.
#131 of 266 Re: 2009 CTS poor mpg [blackcadillac]
Feb 24, 2009 (7:51 am)
Hey "S" Your car and mine sound identically optioned, and I too have questions regarding the gas mileage and sputtering of the engine. Mine also has an idle "flutter" when in or out of gear that will actually cause the car to rock. The dealer of course says that nothing shows up on the diagnostics and that they can't duplicate the same conditions. I'm hoping that the mileage will increase in time as I only have 3400 miles, but the stutter and idle issues are still a concern.
#132 of 266 Re: 2009 CTS poor mpg [ctsguy2]
Feb 24, 2009 (8:46 am)
Wow, I don't know if it's good or bad to hear you're having the same problems.
I also notice the idle flutter.
Are you getting 11/12 MPG?
My dealer also gave me a all OK, based on diagnostic computer hook up when I first brought it in.
Feb 24, 2009 (9:02 am)
No offense, but I was kind happy to hear that someone else was having the same issues and concerns. Comfort in numbers I guess. I haven't checked my mileage in the past few weeks, but on a 500 mile highway trip I got an average of 20.5 and a mixed loop of 15. I calculate my own averages as I don't know how accurate the "DIC" really is.
#134 of 266 Re: [ctsguy2]
Feb 24, 2009 (10:28 am)
Everything I've read suggests you can't rely on the onboard calculations. I have a 2009 Black CTS base engine but have avoided doing any mileage calculations until I hit 7500-10000 miles, which is when I hear engines usually get broken in. So for now, I just enjoy the ride, though I have developed a little rattle in the passengers side seat belt column that I'll have the dealership look at. Otherwise, ok so far.
Good luck guys.
#135 of 266 Re: 2009 CTS Poor MPG
Feb 24, 2009 (11:48 am)
Motor Trend Feb 2009 has a long term test update on their 08 CTS. No doubt it has the DI engine, but it does not say. They reported no problems and a 13,992 mile avg MPG of 17.2
I feel if the combined is 17.2, then their highway could be around 25, which matches up with the EPA estimate.
Assuming you guys with sputtering have a problem, it might not be something that reports a code, if all your service guys are doing to checking for an error code. You might have something wrong like a bad spark plug.
#136 of 266 Re: 2009 CTS Poor MPG [artmbgolf]
Feb 24, 2009 (10:50 pm)
I had a 2004 CTS and a 2006 STS, both with the 3.6L V6 and thought both performed well and had good gas mileage. In October, when I went shopping for a 2009 CTS I thought I would step up to the new 3.6DI. The dealer actually gave me the the car to take home for a 24 hour test drive. I immediately noticed 2 things. First the power increase was noticeable and almost more than necessary. But, secondly, I noticed a pronounced vibration which was very noticeable when the car was stopped at a light. You could feel it in the steering wheel, the brake pedal and even the seat, and you could hear it. I looked at the rpm's to see if I could notice why the car engine seemed to be so rough. But the rpm's looked normal. My wife could even feel this roughness in the passenger seat. But, I still thought this would simply require a minor adjustment, so I returned to the dealer with the intention of buying the car. When I was there, I spoke with the general manager about my impressions of the car and mentioned the engine roughness. And, to my surprise his reply was " Yes I know all about that, I drive one myself and it does the same thing. We can't do anything about it, it's just a characteristic of that engine".
So I left the car there and decided I would investigate this. I went on the internet and read every review I could find. Eventually I found 2 professional reviewers who loved the power of the DI but warned about roughness at idle and slow speeds. Please don't ask me for the reviews, it was 4 months ago and I don't remember.
Ok, so no DI engine for me! I then test drove the old reliable non DI engine and loved it. The power was more than adequate and the refinement was far superior.
As far as mileage goes, my history with Cadillac and the 3.6 V6, has taught me that initial mileage stinks, the mileage on my 2006 STS was still improving at 2 years and 25,0000 miles when I turned it back into the dealer.
My 2009 base CTS got about 10mpg in mostly city on the first tank. The first time I took it on the highway I couldn't get it above 24 mpg. At about 1000 miles I was able to get 26-28 mpg on highway. Now at 2000 miles, I just took a 20 mile trip on I-95 at about 65-70 mph and got 29.5 mpg. Now the city mileage is nothing to write home about, maybe 15 mpg. If you look at the Instant Mileage reading you will see it plummet when you accelerate. So a steady foot will dramatically increase mileage.
Sorry for such a long post, but other things to consider are the weight of the vehicle and the conditions you drive in. AWD adds about 200 lbs, sunroof adds 125lbs. additional options add more weight. I have the base car, doesn't even have the spare tire. Also, I live in South Florida, where the roads are flat, we are at sea level and the weather is always nice.
#137 of 266 Re: 2009 CTS Poor MPG [redgtconv1]
Feb 25, 2009 (7:21 am)
Thanks for the insight. I thought that I had also read somewhere that the 3.6DI had an inherent "design flaw" that caused the idle flutter or roughness, but can't find that blog again.
#138 of 266 Re: 2009 CTS poor mpg [blackcadillac]
Feb 25, 2009 (9:01 am)
Most cars need a break in period before the mileage normalizes. The gas mileage on my 03 CTS got better as it approached 10K miles. The same can be said for my TrailBlazer.
When my wife was driving the CTS 52 miles roundtrip to work on a daily basis, she was averaging 24 - 27 mpg. Now that she only drives 1 to 2 miles roundtrip, she averages 17 - 19 mpg. The engine barely gets to warm up and a car needs some highway miles to achieve better mileage. Trips to the mall (about 5 miles away) actually help raise her average mpg.
Give your CTS some time and don't worry.
#139 of 266 0-60 mph times
Feb 26, 2009 (11:25 am)
I only have approx. 2800 miles on car (2009 cts awd 265 hp engine, auto trans) so I haven't really opened her up yet. Can anyone provide realistic 0-60 mph times for me to expect in the future if I decide to "gas it up" Also, is anyone experiencing the front door stops not being strong enough to hold door open? Meanwhile I'm enjoying the hell out of the car. I forgot how much fun it is to take "the long way home." Getting approx. 17mpg around town, and approx. 26 hiway, no problems to report. Some of my past cars have included TR 3, 65 Beetle, 68 Beetle, 69 pontiac Lemans, 72 Pontiac Firebird 75 BMW 2002, 75 Cadillac Sedan de Ville 75 VW Scirocco, Dodge Omni, Mitsubishi Turbo-Eclipse, Chevy Trailblazer, Toyota Supra, Toyota Corolla, Honda Pilot. (OK, I'm not a kid) So I have a bit of car driving experience--The CTS is the best car I have ever owned!! Regards to everyone.