Boost Mpg's ?

Daniel262

Buick Newbie
4
0
1
S.E. Wisconsin
Buick Ownership
Buick Lucerne '08cxl/ 2010 spl.edition
Thread starter #1
I just bought a 08 cxl and really enjoy the ride and the 3800 iii engine but coming from a 13' Impala that was getting 30+mpg hwy and now getting 22 mpg hwy I am beginning to think I made a big mistake .
This thing is a gas hog and I am driving as easy as possible,can anything be done to increase mpg's.?
I bought my wife 2010 cxl spl.edition with the 3.9l last week 29,650mi and she loves the car,but wants to trade it already bc she is only getting 18mpg city/hwy mix .
Thanks All.
 

Molucerne

Junior Member
16
1
3
Buick Ownership
Buick
#2
Try cleaning the throttle body / air intake. Use Chevron Techron fuel injector cleaner in the gas tank. Try to buy gasoline without an ethanol blend. You've probably done the obvious things such as change the air filter and making sure the tires are properly inflated. My 2007 Lucerne 3800 gets about 28 to 29 MPG driving 70 on rural interstates with small hills. It gets about 18-20 MPG in town.
 

chartny

Buick Newbie
33
3
8
Upstate NY
Buick Ownership
Buick Lucerne '11
#3
I just bought a 08 cxl and really enjoy the ride and the 3800 iii engine but coming from a 13' Impala that was getting 30+mpg hwy and now getting 22 mpg hwy I am beginning to think I made a big mistake .
This thing is a gas hog and I am driving as easy as possible,can anything be done to increase mpg's.?
I bought my wife 2010 cxl spl.edition with the 3.9l last week 29,650mi and she loves the car,but wants to trade it already bc she is only getting 18mpg city/hwy mix .
Thanks All.
For what it is worth. Example. I bought a used Lin Cont, 9.5 years old pristine in VA. Drove it 6 year 3 months. Original owner my estimate 70cents per mile depreciation, my cost per mile 13.3 per mile. Next example: Just bought '11 Lucerne. Well south of the rust belt, pristine car, original owner estimate 40 cents per mile. My expected cost of depreciation, should be 13 per mile. Difference $0.27 per mile.
Now real math. I just gassed up in NY State, high gas price. $2.69. At 20 mpg cost per mile $0.1345. At 25 mpg cost per mile $0.1076. Difference $0.027. Just coincidence but cost per mile for a nice used car vs new $0.27 per mile. Note 10X the cost for 20 vs 25 mpg. For me, big costs matter most, little cost, not important. No guarantee my math inputs to my spread sheet are correct.

-chart-
 

NEIA Nomad

Buick Newbie
8
1
3
NEIA
Buick Ownership
Buick Regal Turbo
#4
On my old S10 I kept adding, and changing parts for better MPG, but after a week it would go right back to about 14mpg. I talked to a guy who ended up reprogramming my computer, and removing VATS, along with some other witchcraft. That S10 averages 20MPG now. Your best bet is to have the computer fiddled with. I had PCM powertunes do mine. I haven't talked to him about my Regal yet because of the warranty.
______________________________
 

chartny

Buick Newbie
33
3
8
Upstate NY
Buick Ownership
Buick Lucerne '11
#5
One more thing: top of the list of less MPG than expected. Dragging brakes. My Lucerne '11 ~60K miles has two dragging. Left front, no grease on one guide pin on the caliper, nearly stuck tight but I managed to get it free with significant work. No grease at all in it. Cleaned and greased and it moves fine. Right rear, parking brake not releasing. looks like the cable is stuck. I used a big screw driver and pushed the lever back on the caliper and it is free so I will not use the parking brake till warmer weather. Quick test is to check for rotor temperature side to side. They should be the same after a short around the block drive.
Next old issue: Daughter's Terraza '05. Bought from GM dealer who put on new rotors and pads all around. Son-inlaw calls and told me the fronts are hot after one mile drive. He had good garage floor so I jacked it up and the front was so tight I could not turn the wheel. Pulled the wheel and pulled the caliper and still stuck. Pads were so tight I had to use a heavy screwdriver and hammer to get them out of the guides. They had burrs on the stamping digging in the guides. GM parts. I got new pads at Autozone and had him back on the road for the next day's work. He then noted the rears were too warm and took it back to dealer. They found the rear wheel bearings loose letting the wheel/rotor move and rub the pads. New rear hubs and it was fine. These under warranty. Vehicle at 15K had to have OE rotors and pads replaced, and then still issues.
Point: it takes a lot of gas to wear out pads.

-chart-
 

vanwitt

Junior Member
28
1
3
Buick Ownership
Buick
#6
My routine when buying used cars is to start with the Chevron Techron.
Run a bottle of Auto-RX through the crankcase.
Use Top Tier gasoline.
Use full synthetic oil.
Pump tires up to 35 - 38 pounds.
Set the cruise on 60 mph.
I have had up to 33 mpg on the highway but my wife drives the car mostly in the city with a fully thorough warm-up only occasionally happening and she gets 15 plus mpg.
Winter fuel lowers the mpg by one or two.
Yep, it is just a gas hog, it is a big heavy car, and that is part of the reason, I think for its beautiful ride.
I do fantasize about a power tune once in a while, though.
 

Daniel262

Buick Newbie
4
0
1
S.E. Wisconsin
Buick Ownership
Buick Lucerne '08cxl/ 2010 spl.edition
Thread starter #7
Thanks for all the replies, they are all very helpful ,I plan on dropping the trans pan this weekend and doing the filter and magnet service so I will definitely pull all 4 wheels and check the brakes too.
My wife is doing the Dave Ramsey budget thing right now so she's a little concerned about mpg's but also does not want to give up the heated steering wheel and seats , so I told her life is give and take and she's fine with it now.
 
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