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Buick Lucerne: Real World MPG



  • We get 30+ mpg but that's only on the interstate. Around town we average 20-25. '06 CX, V-6.
  • taraleetaralee Posts: 13
    My husband and I love the car, the ride, and all the "Cadillac" amenities that came with it....BUT, From the time I brought my Lucerne CXL 3.8 6 cyl home, I've dealt with bad gas mileage ranging from 16mpg to 22mpg even on the highway. A mechanic friend of mine suggested that I change my existing oil from the factory oil to "full synthetic" oil to see if that would help. It did help, it went up to 29-32 mpg immediately! It rocked on for 6 months doing great, now it has fallen back to 22mpg or less. I have addressed it with the dealership from the git go. I have heard everything from, "it's bad gas" to "every vehicle has a break in period, give it some time." Well I have 15,800 miles on it and still getting bad mileage....I took it in to the dealership last week and they did a computer diagnostic and found no codes whatsoever! They didn't even bother trying other solutions like changing the fuel filter, or checking for a crimped fuel line, they sent it home telling me "if it gets any worse, bring it back." :confuse:
  • With 6500 miles, the gas mileage has improved only about 1 MPG since new. I think I will wait until it gets about 8000 on it to start complaining to the dealer more so I don't get the "break in" answer.
    Taralee: which brand and weight of oil did you use to get the mileage to jump? Thanks.
  • My wife and I just finished a road trip (1360 miles) around the state (WI) and the DIC said we averaged 30.8 mpg ... doing it long hand (miles traveled divided by gallons of gas purchased) was within a couple tenths of a mpg. I use the basic 5W-30 oil the dealerdship puts in at oil changes. I do put in a bottle of injector cleaner after each oil change, not sure if that helps but I figure it can't hurt.
  • taraleetaralee Posts: 13
    Yes, I calculate my mileage the same way. I was advised not to add injector cleaner until the car gets over 35,000 miles on it. We have done some checking with various mechanics and it is their opinion that our problem may lie with the computer chip that regulates the injectors and the timing. There are so many happy Lucerne owners here with great gas mileage that I am almost certain that mine just has a bad chip or a lemon off the assembly line. I will contact Buick this week and post their reply to this problem.
  • taraleetaralee Posts: 13
    Castrol Syntec 5W-30 full synthetic. It's expensive but it sure was worth the change for a little while :) I told the mechanics at the dealership what I did, and they had no problem with me changing the brand of oil as long as the oil is the approved weight and specifications dictated in the manual.
  • Have averaged 21.1 MPG combined city and highway for the first 6700 miles. Would like to learn of other owners' experiences with this engine.
  • grisbygrisby Posts: 2
    I have the CXL with the 4.6 Northstar and combined city and hiway I am getting about 20.8 mpg. I have 5900 miles on it now. I recently took a trip to Fla (I live in PA) and the best tank got me 26.6 mpg with an overall average for the trip of 24mpg.
  • I found with my CXS (V8) that I can achieve 30 - 31 MPG, but there is one catch. I can only obtain this on Highway traveling at 53 MPH! At 55 MPH 29 - 30 MPG.

    I would say the Bucik Engineers did not consider gas economy when considering gear ratios. A 6 speed transmission is a must with 100 dollar a barrel oil prices.
  • I see the government has posted its new mpg ratings for the 6 cylinder Lucerne as 16 mpg city - 26 mpg highway and combined 20 mpg. Sounds more like what many of us are getting. I do not understand how people are claiming to get over 30 mpg highway and 25 or 26 combined are getting it. I wish I had their luck.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,045
    >A 6 speed transmission is a must with 100 dollar a barrel oil prices.

    Actually it's odd you'd say that. More speeds are needed if your motors have little torque at low revolutions. So you add speeds to be able to keep the motor turning at 3000 and up as people accelerate briskly; or you do that to keep the motor reving high upon slight push on the gas pedal demanding acceleration which the motor can't give at 1500-1800 due to low torque. Hence you have the tranny downshift.

    Your NorthStar V8 has gobs of torque and performs nicely in most of the 4 gears. Adding a speed might gain a slight fuel economy edge, depending on the test cycle speeds involved. Trouble is most people don't drive like the test cycles used at EPA to garner info about mileage.

    My 3800 motor has more than adequate acceleration with a 4 speed transmission. I don't accelerate at full throttle often. The people getting low 20s in everyday driving are probably doing mostly short trips under 10 miles and running on a cold motor often using lots of extra gas because of that. They also may, I said may, accelerate differently than I do from the stop signs every mile and the stop lights. I'm not in a hurry but I usually catch the jackrabbits who accelerate quickly and go within 5 of the speed limit. They don't gain a thing. My one car gives 24 in mixed driving; the older car is giving about 22-20 because of lots of short trips of 4 miles on cold motor.

    If you can take you car out on the open interstate and push the reset button on the mileage and show an average of 28 and above while cruising at 65 or so, I'd feel I'm doing great.

    Oddly the WunderKar from Honda only has a 5 speed transmission.
  • If I do an all interstate trip, I'm often close to 30, while regular driving around is around 24. In pure city driving I'm sure the weight of the car would make the MPG suffer a lot. I find the 4 speed just fine with the V6 and it has plenty of power for normal driving. I wonder what these auto writers expect of a car, maybe they get spoiled from driving fast cars every day, how fast do you need to accelerate in normal driving?
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,045
    The magazine testers spend their days driving like hotdogs. Many people who are car fanatics and are here on Edmunds (most of us?) don't drive like average drivers.

    But for 90% of drivers, the 3800 and 4 speeds are more than adequate.
  • thegraduatethegraduate Posts: 9,731
    True. It's why so many people choose 4-cyl versions of midsize cars (like I did). While the 4-cyl Accord I chose is faster than the V6 Lucerne, I'd imagine the 3800 Lucerne is plenty to keep you safe, if not great at highway passing.
  • I have notice the sweet spot is 54MPH - close to what you see but I do nt get 31MPH but mor like 28MPH. I once got 29 and change.

    I am also surprised that just increasing speed to 55 - 57 MPH a 10 % drop in mileage- not sure why either since lockup converter is engaged a at both speeds.

    I be interested in the octane of gas which you got your mileage. Also I hear that the level of ethenol affects mileage.
  • I use plain 87 octane with 10% ethanol. I don't WANT to use that junk but I don't have other choice. I have found that my "sweet spot" is between 60 and 65.
  • According to the Driver Information Center (DIC) my Lucerne is getting an average of 25.0 MPG. My old 2000 LeSabre was getting 28.6, and that was with 160,000 miles on the odometer. Same engine and transmission in both cars.

    The Lucerne is a terrible car all around. Thankfully, when I want to drive a smooth, quiet, well made vehicle, I can still take my old LeSabre out as it is now my wifes car.
  • Then get rid of the Lucerne. Personally, we love ours. Mileage of 30+ on the highway no problem.
  • I've had my Lucerne for a year and a half now. I've had people tell me how happy they are with theirs and what great mileage they get....Personally, I've never gotten over 23 mpg with mine! :mad: There are very few people here that have the problem that you and I do with our Lucernes. It's not the way we drive our cars. It's not the roads. It may be the fuel, but I've tried them all and none seem to make a difference. I changed over to full synthetic oil, I have tried fuel injector cleaners, NOTHING WORKS....I even had the dealership open a service file and they kept my car for 3 weeks trying to remedy the problem. They consulted with Buick (Buick was clueless), they sent it home with no remedy. I believe there are some Lemon Lucernes out there coming off the assembly lines and either Buick doesn't know how to remedy the problem, or won't...Either way, I'll keep the car for awhile longer until I pay the note down, then I'll trade it in.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,045
    >Personally, I've never gotten over 23 mpg with

    Telll us about the area where you live as far as the type of driving you do. How close are the stoplights? Are you on the freeway?

    What mileage do you get when you take a long drive on a highway without stoplights? When you reset the MPG gauge while you're rolling on an open highway with the car warmed up, what kind of mileage do you get?
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