I'm curious to see what kind of MPG everybody with a 00+ DeVille gets. I just want to make sure I'm getting the best MPG as possible with gas prices like they are.

I've got 53k miles on the 2000 DeVille and get around 15-16 mpg, usually 15.4. I calculate that myself, I don't use the digitial display. TIA

If you are getting that mileage around town, then that is par for the course, being a 2000 you are able to use regular gas, on the highway, you should get about 23 to 29+ mpg, unless you drive at about 85 to 90 or you have lots of hills to go up and down. I don't know if those 20 inch wheels have anything to do with it, someone more knowledgeable about tires and rims can chime in on that one. Remember, as expensive as gasoline is, its still better than public transit.

I travel round trip maybe 16 miles to work, and close to half of that is highway. No hills down here in South Florida either. I did just notice the other day the front tires need some air in them which doesn't help. I was hoping for atleast near 19 mpg or so.

i have a 01 DTS, and i get about 17mpg city, but i have no hills. the 20s if your running a 255/35zr20 then your spedo will be the same and your mpg will be the same as the factory 17's on a dts.

02 Base Deville, 130K miles

Melissa put over 40K miles on it in one year. Travel from home to Pennsauken, Princeton, North Jersey, etc. 80-90% rapid highway driving, 10% rural/suburban, 10% Stop-N-Go.

Her average on regular gas for about the last 5 months (since she never plays with the DIC settings...) is 24.1 miles per gallon.

Can't complain. Especially since she has a fleet gas card anyway... lol

I have a 2000 DeVille and get an average of just over 24 miles per gallon. I use the DIC to track milage. Also, I believe that all Northstar engines required premium gasoline so I don't use anything but premium. As far as fuel efficiency, my DeVille is better than my 2004 Chevy S10 V6. The S10 uses regular gas and averages just under 20 MPG so I am getting better than 20% more with the Caddy and paying only about 10% more for the premium gas.:)

EPA rated at 17mpg city 27 hw i believe. Which is pretty impressive since they are such large cars.

In Answer To A Question Regarding Premium Required & Recommended:

The 96/97 Northstars actually went from a "premium required" to a " premium recommmended" fuel requirement. The premium fuel "required" was eliminated from the dash and gas cap on the 97 models I think.... That was done purely because the 93/99 Northstar engines are very tolerant of mid grade and regular fuel under most all conditions. The engine compression ratio and combustion chamber was not modified in the least to do this. The engine is still optimized to make the most power on premium fuel. They will not necessarily make full power on lower octane fuels but they drive fine and will not be damaged at all.

The 2000 and later engines are completely redesigned and the combustion chamber and compression ratio were modified substantially to allow operation on regular fuel. Under some severe conditions (very hot , dry weater) the use of premium might add a little power but for most all of the people in most all of the driving conditions in the US the use of regular in the 2000 and later engines is fine.

Despite your observations there is no way that the use of regular fuel caused any damage to the spark plugs or wires. Both the earlier engines and the 2000 and later engines are tested on regular fuel for spark plug preignition resistence to make sure that nothing will be damaged by lower octane fuels. The quality of the fuel you bought may have had an effect on spark plug deposits or something...but that had nothing to do with the octane rating of the fuel.