Buick lucerne

The 2006 should have a 3800 v6 engine which is an excellant engine choice. That engine in a Lesabre will get 30 mpg and maybe a little less in the Lucerne which is a little heavier. IF the '06 has the Northstar v8 which was an option, I don't think you want that engine for economy.

I have a 2007 4.6L (V-8) Lucerne. This is by far my favorite big grocery getter in my 53 years of driving. It's comfortable, quiet, corners wonderfully (magnetic ride control option probably helps), and accerlerates and brakes well enough to satisfy my inner hot-rodder. I like it much better than any of the BMW and Lexus big cars that my daughter has owned, and it is much cheaper to maintain. The down side is that the V-8 has gotten 18.8 MPG over the last 50K miles - driven with a pretty heavy foot, about 75% city driving. I doubt I could get it above 20 MPG. On the other hand, while the 3.8L V-6 is probably the best engine GM has ever produced, it is pretty much dog in the heavy Lucerne. I was not willing to put my wife in it trying to merge with Austin's manic traffic. I'd buy another one in a minute if I wrecked this one, but you'll have to decide (as is aways the case) your own balance between performance and its inevitable cost.

I had a 2007 CXS Lucerne and it would get 25 on the interstate at 70mph. That was with 90K miles. I really liked the car but needed to thin the herd. You may have a bad sensor, the knock sensor will retard the timing if bad and give you poor performance and poor gas mileage. PS I live in Georgetown

Yeah, I get 25-26 on the highway with the 4.6L, too. The 18.8 is the average since I bought the car. If you live in Georgetown, you know that much Austin driving is at 0 MPG to match the 0 MPH.

No.