98deville Posted June 4, 2007 Report Share Posted June 4, 2007 Eversince I bought my 2003 dts it seems to waste alot of gas...more than my 98 deville..I can go to austin (which is 35 to 40 miles there and the same coming back) on a full tank of gas and have about a half a tank of gas when i get back...could it be that it has more power than the 98 so it uses alot more gas...or is there something wrong? I can get close to 300 miles on a full tank of gas. Does this sound good? Link to comment Share on other sites More sharing options...
Ranger Posted June 4, 2007 Report Share Posted June 4, 2007 The DTS has a 3.71 final drive as opposed to the Devilles 3.11, thus will get about 3 MPG less. Link to comment Share on other sites More sharing options...
95SevilleSLS Posted June 4, 2007 Report Share Posted June 4, 2007 Half a tank on 80 miles seems a bit steep. I have a STS and can get about 300 miles on a tank. Check your mileage through your DIC (average MPG) and report back on your mileage. I'm interested in seeing what your coputer says you are getting for mileage. -Dusty- - 02 Seville STS, white diamond - 93 Sixty Special, Tan with vinyl top - 79 Coupe DeVille, Tan with Tan top - 06 GMC Sierra Z71, Black - 92 Silverado C1500, black and grey - 83 Chevy K10 Silverado, Black and Grey Link to comment Share on other sites More sharing options...
John Wicz Posted June 4, 2007 Report Share Posted June 4, 2007 I'm getting 17~18 MPG with my '03 DTS in combined driving, lots of stop lights............ Link to comment Share on other sites More sharing options...
98deville Posted June 4, 2007 Author Report Share Posted June 4, 2007 Half a tank on 80 miles seems a bit steep. I have a STS and can get about 300 miles on a tank. Check your mileage through your DIC (average MPG) and report back on your mileage. I'm interested in seeing what your coputer says you are getting for mileage. will do Link to comment Share on other sites More sharing options...
98deville Posted June 6, 2007 Author Report Share Posted June 6, 2007 I checked the average MPG on my DIC and the number jumps around it went from 14 to 15 to 55 then back down to 14 MPG. On a full tank of gas the dts gets 285 miles, thats driving in town and on the highway very little..How come it's getting poor mileage ...my 98 deville d'elegance can get close to 400 miles on a full tank Link to comment Share on other sites More sharing options...
2004SLS Posted June 6, 2007 Report Share Posted June 6, 2007 I checked the average MPG on my DIC and the number jumps around it went from 14 to 15 to 55 then back down to 14 MPG. On a full tank of gas the dts gets 285 miles, thats driving in town and on the highway very little..How come it's getting poor mileage ...my 98 deville d'elegance can get close to 400 miles on a full tank Does the 98 have a much larger gas tank? Link to comment Share on other sites More sharing options...
JimD Posted June 6, 2007 Report Share Posted June 6, 2007 I checked the average MPG on my DIC and the number jumps around it went from 14 to 15 to 55 then back down to 14 MPG. That sounds like you are displaying instantaneous MPG instead of average MPG. And the overall fuel economy sounds like a leaking fuel injector or leaking fuel pressure regulator or some other leak in the fuel plumbing that is dumping fuel somewhere other than in the engine. If the leak is external to the engine, you should be able to smell fuel vapors. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
98deville Posted July 8, 2007 Author Report Share Posted July 8, 2007 I just recently noticed that when accelerating the RPM's go up real high around 4000rpms and that just accelerating to 40mph. Is this normal, should the rpm's be going that high under normal acceleration...thats probly where all the gas goes... Link to comment Share on other sites More sharing options...
98deville Posted July 8, 2007 Author Report Share Posted July 8, 2007 I checked the average MPG on my DIC and the number jumps around it went from 14 to 15 to 55 then back down to 14 MPG. On a full tank of gas the dts gets 285 miles, thats driving in town and on the highway very little..How come it's getting poor mileage ...my 98 deville d'elegance can get close to 400 miles on a full tank Does the 98 have a much larger gas tank? They both have the same size gas tanks if I'm not mistaken Link to comment Share on other sites More sharing options...
daniel812 Posted July 8, 2007 Report Share Posted July 8, 2007 Where is the fuel pressure regulator located in my 1998 SLS?? Link to comment Share on other sites More sharing options...
Ranger Posted July 8, 2007 Report Share Posted July 8, 2007 On the fuel rail. It has a vacuum line attached. Link to comment Share on other sites More sharing options...
Poobah Posted July 9, 2007 Report Share Posted July 9, 2007 As a point of comparison, my base model 2000 Deville gets between 18 and 19 MPG (right now the DIC shows 18.1 MPG average). That's a mix of highway and city driving. If I zero out the average MPG reading at the start of a trip, I'll get a little over 19 MPG for highway driving. My owner's manual says the fuel tank holds 18.5 gallons but I get the "Low Fuel" warning after using about 15.5 gallons. I rarely let it go past 16.5 gallons used. I generally get just under 300 miles per tank of gas. Happiness is owning a Cadillac with no codes. Link to comment Share on other sites More sharing options...
KHE Posted July 9, 2007 Report Share Posted July 9, 2007 I wonder if the catalytic converter could be plugged. Does the car lack power? Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
Hud Posted July 10, 2007 Report Share Posted July 10, 2007 On my 02 DTS, I get 13.8 in town and 24.5 on trips. Link to comment Share on other sites More sharing options...
growe3 Posted July 12, 2007 Report Share Posted July 12, 2007 On my 04 DTS I get 19.4, mostly freeway. This is very close to my 93 STS which gets 19.6 average. The DTS is about 180 lbs. heavier, which is negligible. -George Drive'em like you own 'em. - ....................04 DTS............................ Link to comment Share on other sites More sharing options...
98deville Posted July 30, 2007 Author Report Share Posted July 30, 2007 on the display it said 16.5 MPG Avg. Link to comment Share on other sites More sharing options...
JohnnyG Posted July 30, 2007 Report Share Posted July 30, 2007 on the display it said 16.5 MPG Avg. The point is, Avg mpg should not "jump around" It should be a relatively stable reading since it is an average. I will say that some computer programs have change recently, and I'm not sure that Cadillac has ever adopted the newer version. I say newer because there is a HUGE difference in the way my 2007 Dodge Ram calculates "average" when compared to my '99 STS. The Dodge seems to start the new average using the CURRENT average as the starting number. My '99 STS started the calculations using the current INSTANTANEOUS mileage as the starting point. A very big difference in reality. In either case though, only the instantaneous MPG indicator "jumps around" very much. SO, when you are driving on the highway at a steady speed, cruise control ON, and you reset the instantaneous mpg reading, what do you get as a result? Doing that on my 99 tells me I'm getting about 27.5 mpg........straight and level road, 70 MPH. Never underestimate the amount of a persons greed. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.