weephee Posted July 7, 2005 Report Share Posted July 7, 2005 Hi Guys, I tried to look this up in History but couldn't find anything. I have a 99 STS and a 2000 STS. Both of these cars get about 23 MPG. That is the best they get driving with premium fuel, no AC on and travelling about 60 mph. The window sticker on these cars claim they get 35 mpg on the Hwy. I understand that is not realistic but the difference between 23 and 35 is a lot. I have changed the plugs, wires on the 99, fuel filters and cleaned the injectors. What kind of mileage do the rest of you get. Again, I tried to find a poll in the history but couldn't. Any help or comments greatly appreciated. Link to comment Share on other sites More sharing options...
JimD Posted July 7, 2005 Report Share Posted July 7, 2005 My '98 has averaged 21 MPG over 14x,000 miles. Never higher than 25 on the Interstate and usually closer to 22. This car sees a lot of Interstate miles and very few short trips. I have a heavy right foot and tend to keep the carbon from accumulating in that tiny combustion chamber. When gasoline approaches $4.00 per gallon, I might consider changing my driving habits. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
JimD Posted July 7, 2005 Report Share Posted July 7, 2005 BTW: my window sticker says 17 and 26. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
graphite-sts Posted July 7, 2005 Report Share Posted July 7, 2005 My 01 gets 20mpg under normal conditions, when I'm not jumping on it. And that's on reformulated crap. I would probably get about 2mpg better on normal gas. Window stickers are BS, I bought my '90 Dodge Ram new, and the sticker said, 17-21, It never got over 13. Jim Link to comment Share on other sites More sharing options...
Ranger Posted July 7, 2005 Report Share Posted July 7, 2005 22 winter , 24 summer, mostly highway. Best ever was 30 on a 300 mile trip, cruise set at 70, A/C on. Link to comment Share on other sites More sharing options...
Bob D Posted July 7, 2005 Report Share Posted July 7, 2005 wee...where did those stickers come from? Sounds dubious to me. I think Jim D's got the correct sticker at 17/22. I know with my STS I get ~20 around town, and 23 on the long hauls. In a 4000 lb, high performance sedan, that is NOTHING to complain about. (especially with my driving techniques..) '93 STS.. opened, dropped, wide...fast. Link to comment Share on other sites More sharing options...
tjtjwdad Posted July 8, 2005 Report Share Posted July 8, 2005 I've gotten as high as 30.5 with my 01 STS (avg speed 62 MPH). Driving 75 MPH is up around 26 MPG. This is with the AC off, with cruise control and maintaing a steady speed. Jim Link to comment Share on other sites More sharing options...
fubar0715 Posted July 8, 2005 Report Share Posted July 8, 2005 I post a few days ago about changing my wire and plugs in my STS. Prior to that I was getting about 15-16mpg in mixed interstate and city driving. I use my STS for commuting back and forth to work primarily and its 4 miles to the interstate, 16 miles on the interstate, and 5 miles to work once I get off the interstate...I am getting about 18.5 now with the new plugs and wires..Best ever was 21 on a long road trip to Savannah....BTW my STS has 149k on the clock!!!!! Link to comment Share on other sites More sharing options...
KevinW Posted July 8, 2005 Report Share Posted July 8, 2005 The window sticker on these cars claim they get 35 mpg on the Hwy. I understand that is not realistic but the difference between 23 and 35 is a lot. I think you're quoting an EPA highway estimated miles per Imperial gallon of fuel. The on-board mileage readout shows the miles per U.S. gallon; add 20.1% to correct (4.546 L per Imperial gallon / 3.785 L per U.S. gallon). I believe that the EPA estimated figures are based on the most popular driveline configuration (3.11 final drive, 275 hp engine). I would expect lower average fuel economy figures with the 3.71/300 hp combination. ___________________________________________________ Link to comment Share on other sites More sharing options...
JIMDTS Posted July 8, 2005 Report Share Posted July 8, 2005 Around town I get 15 or 16 mpg on the highway I'v had as high as 28 mpg but that was just cruising along at 70 I don't baby the car so the gas milage goes way down when you push down hard on the gas pedal. I do a few wot's a day and the milage shows it.. Cheers Jim Link to comment Share on other sites More sharing options...
KHE Posted July 8, 2005 Report Share Posted July 8, 2005 Hi Guys, I tried to look this up in History but couldn't find anything. I have a 99 STS and a 2000 STS. Both of these cars get about 23 MPG. That is the best they get driving with premium fuel, no AC on and travelling about 60 mph. The window sticker on these cars claim they get 35 mpg on the Hwy. I understand that is not realistic but the difference between 23 and 35 is a lot. I have changed the plugs, wires on the 99, fuel filters and cleaned the injectors. What kind of mileage do the rest of you get. Again, I tried to find a poll in the history but couldn't. Any help or comments greatly appreciated. I'd like to see the window sticker that said 35 MPG highway... Those cars were rated 17 city 26 highway......... Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
Bob*97 SLS Posted July 8, 2005 Report Share Posted July 8, 2005 I usually average 23-25 in city and I will usually get 33-35 on the Hwy while traveling. Since I'm in the south, my air is always on. Link to comment Share on other sites More sharing options...
CaddyChris Posted July 8, 2005 Report Share Posted July 8, 2005 wee...where did those stickers come from? Sounds dubious to me. I think Jim D's got the correct sticker at 17/22. I know with my STS I get ~20 around town, and 23 on the long hauls. In a 4000 lb, high performance sedan, that is NOTHING to complain about. (especially with my driving techniques..) Hey Bob, Does your 93 have the northstar? how the hell do you get 20mpg around town. I average 13.5 mpg in my STS. On the highway I can get 20mpg. I drive to work in a mixed environment and still get ~13. Its tough on the way home with all the traffic not to gun it. Do you think I need to look into plugs and wires. I put new acdelco plugs in about 8000 miles ago with the "new" engine. What about wires? What do you or anyone else think? Thanks. Chris Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
Bob D Posted July 8, 2005 Report Share Posted July 8, 2005 wee...where did those stickers come from? Sounds dubious to me. I think Jim D's got the correct sticker at 17/25. I know with my STS I get ~20 around town, and 23 on the long hauls. In a 4000 lb, high performance sedan, that is NOTHING to complain about. (especially with my driving techniques..) Hey Bob, Does your 93 have the northstar? how the hell do you get 20mpg around town. I average 13.5 mpg in my STS. On the highway I can get 20mpg. I drive to work in a mixed environment and still get ~13. Its tough on the way home with all the traffic not to gun it. Do you think I need to look into plugs and wires. I put new acdelco plugs in about 8000 miles ago with the "new" engine. What about wires? What do you or anyone else think? Thanks. Chris Yep, it sure does have a N*.., and that's with 255/50x16 tires (higher rolling resistance than stock). The mpg actually dropped ~2 mpg (used to avg. 22), when I made that change some time ago now. If I drive the car really hard, (lots of WOT) it will drop to 18, but I've never seen it go below that no matter what I do. And I do LOT of driving in the hills..My plugs and wires btw are original, no problems there.. Back to basics, what kind of tires and pressures are you running? Check the air cleaner lately? I'm trying to think here...catalytic converter flowing well? (exahust restriction..)..Hmm.. '93 STS.. opened, dropped, wide...fast. Link to comment Share on other sites More sharing options...
CaddyChris Posted July 8, 2005 Report Share Posted July 8, 2005 wee...where did those stickers come from? Sounds dubious to me. I think Jim D's got the correct sticker at 17/25. I know with my STS I get ~20 around town, and 23 on the long hauls. In a 4000 lb, high performance sedan, that is NOTHING to complain about. (especially with my driving techniques..) Hey Bob, Does your 93 have the northstar? how the hell do you get 20mpg around town. I average 13.5 mpg in my STS. On the highway I can get 20mpg. I drive to work in a mixed environment and still get ~13. Its tough on the way home with all the traffic not to gun it. Do you think I need to look into plugs and wires. I put new acdelco plugs in about 8000 miles ago with the "new" engine. What about wires? What do you or anyone else think? Thanks. Chris Yep, it sure does have a N*.., and that's with 255/50x16 tires (higher rolling resistance than stock). The mpg actually dropped ~2 mpg (used to avg. 22), when I made that change some time ago now. If I drive the car really hard, (lots of WOT) it will drop to 18, but I've never seen it go below that no matter what I do. And I do LOT of driving in the hills..My plugs and wires btw are original, no problems there.. Back to basics, what kind of tires and pressures are you running? Check the air cleaner lately? I'm trying to think here...catalytic converter flowing well? (exahust restriction..)..Hmm.. Hmmmm...thanks for the reply. Well, I don't know the tire size exactly but I can tell you that I have the 17" dts wheels from 2000. I have goodyear RSA tires. I keep them inflated at 32psi. I havn't taken a look at the air filter at all. I 'll have to check that. The exhaust is all stock...how would one diagnose if it was flowing well or not? Thanks. I'll put my signature on so you can see the wheels. I don't always include it cause it is so wide. Do you have any recommendations on an airfilter...I'm pretty sure I need a new one...just go to Pep boys and get an OEM one or what? Thanks. Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
CaddyChris Posted July 8, 2005 Report Share Posted July 8, 2005 Oh yes...the wires probably need to be replaced. Should I start with wires and an air filter? I am gonna do it this weekend...wires, air filter, oil change, psi check on the tires. 18mpg is pretty remarkable for being rough on it. That is my problem sometimes... I love the WOT Chris Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
Bob D Posted July 8, 2005 Report Share Posted July 8, 2005 wee...where did those stickers come from? Sounds dubious to me. I think Jim D's got the correct sticker at 17/25. I know with my STS I get ~20 around town, and 23 on the long hauls. In a 4000 lb, high performance sedan, that is NOTHING to complain about. (especially with my driving techniques..) Hey Bob, Does your 93 have the northstar? how the hell do you get 20mpg around town. I average 13.5 mpg in my STS. On the highway I can get 20mpg. I drive to work in a mixed environment and still get ~13. Its tough on the way home with all the traffic not to gun it. Do you think I need to look into plugs and wires. I put new acdelco plugs in about 8000 miles ago with the "new" engine. What about wires? What do you or anyone else think? Thanks. Chris Yep, it sure does have a N*.., and that's with 255/50x16 tires (higher rolling resistance than stock). The mpg actually dropped ~2 mpg (used to avg. 22), when I made that change some time ago now. If I drive the car really hard, (lots of WOT) it will drop to 18, but I've never seen it go below that no matter what I do. And I do LOT of driving in the hills..My plugs and wires btw are original, no problems there.. Back to basics, what kind of tires and pressures are you running? Check the air cleaner lately? I'm trying to think here...catalytic converter flowing well? (exahust restriction..)..Hmm.. Hmmmm...thanks for the reply. Well, I don't know the tire size exactly but I can tell you that I have the 17" dts wheels from 2000. I have goodyear RSA tires. I keep them inflated at 32psi. I havn't taken a look at the air filter at all. I 'll have to check that. The exhaust is all stock...how would one diagnose if it was flowing well or not? Thanks. I'll put my signature on so you can see the wheels. I don't always include it cause it is so wide. Do you have any recommendations on an airfilter...I'm pretty sure I need a new one...just go to Pep boys and get an OEM one or what? Thanks. Well, the higher the psi, the better the mpg's by a bit, but I'm running 32 as well. A poorly flowing air filter can make a big diference! Try that first. Don't waste your money on any of those filters with the big claims. It's been proven time and time again that a good paper one is just fine. Let us know if that one change really helped. Good luck. '93 STS.. opened, dropped, wide...fast. Link to comment Share on other sites More sharing options...
CaddyChris Posted July 8, 2005 Report Share Posted July 8, 2005 Thats what I'm gonna do. I will keep you guys posted. Thanks Bob. Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
Bob D Posted July 8, 2005 Report Share Posted July 8, 2005 Oh yes...the wires probably need to be replaced. Should I start with wires and an air filter? I am gonna do it this weekend...wires, air filter, oil change, psi check on the tires. 18mpg is pretty remarkable for being rough on it. That is my problem sometimes... I love the WOT Chris Are you sure you nees wires? Is it missing, running rough? Before I'd go to that trouble and expense, I'd start the motor at night in a dark place, open the hood and spray the wires with a 'water mister' (you know, like for plants) bottle. If it's not missing, and you don't see any fireworks (arcing) don't bother. If you must change the wires, it comes highly recommended thar you use OEM (AC Delco) wires. Anything may lead to more problems. Also, when routing them MAKE SURE you follow the original setup, and keep them away from the HVAC blower housing. Spark plugs wires close to that have been proven to burn ther motor out, another headache you really dont want. '93 STS.. opened, dropped, wide...fast. Link to comment Share on other sites More sharing options...
CaddyChris Posted July 8, 2005 Report Share Posted July 8, 2005 Oh yes...the wires probably need to be replaced. Should I start with wires and an air filter? I am gonna do it this weekend...wires, air filter, oil change, psi check on the tires. 18mpg is pretty remarkable for being rough on it. That is my problem sometimes... I love the WOT Chris Are you sure you nees wires? Is it missing, running rough? Before I'd go to that trouble and expense, I'd start the motor at night in a dark place, open the hood and spray the wires with a 'water mister' (you know, like for plants) bottle. If it's not missing, and you don't see any fireworks (arcing) don't bother. If you must change the wires, it comes highly recommended thar you use OEM (AC Delco) wires. Anything may lead to more problems. Also, when routing them MAKE SURE you follow the original setup, and keep them away from the HVAC blower housing. Spark plugs wires close to that have been proven to burn ther motor out, another headache you really dont want. Well, there is a problem when it starts cold but I don't think its related to wires. What happens is...only sometimes...I start it and it will either start rough like the engine is loaded up. Idle will stay high at about 950 and it will run rough until normal operating temp is reached. I think it is a leaky injector. As far as missing...it does not. I probably do not need wires. I will do that test and see how it turns out. I can get delco wires at almost cost so I don't think it will be too bad. I'll concentrate on that and the air filter. The leaky injector is another story. Ill post as I get some results. Thanks again. Chris Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
dpsq Posted July 8, 2005 Report Share Posted July 8, 2005 I have a 99 STS and averaged 19.6 MPG until I had new crank sensors and a new EGR valve installed...mileage dropped to an average of 18.6. all this was on premium fuel. I've read on thsi forum that regular was OK, so last month I tried it. I could discern no change in performance, but I strip my gears and call me shiftless, if my mileage didn't jump back up to 19.6! go figure! Any opinions on that? no difference in driving parameters. Link to comment Share on other sites More sharing options...
DFBonnett Posted July 8, 2005 Report Share Posted July 8, 2005 15 mpg, mixed local/highway. Link to comment Share on other sites More sharing options...
Ranger Posted July 8, 2005 Report Share Posted July 8, 2005 A poorly flowing air filter can make a big diference! Didn't we "debate" this not long ago? Link to comment Share on other sites More sharing options...
Bob D Posted July 8, 2005 Report Share Posted July 8, 2005 A poorly flowing air filter can make a big diference! Didn't we "debate" this not long ago? Yeah, we did, and I've got to admit I'm still thinking old school... (carbs)..But, the way I read his post, he had no idea what the condition of the air cleaner was. I think that was worth looking into.. '93 STS.. opened, dropped, wide...fast. Link to comment Share on other sites More sharing options...
Scotty Posted July 8, 2005 Report Share Posted July 8, 2005 Don't feel bad, I made the same mistake and Guru set me straight... We are showing our age guys Link to comment Share on other sites More sharing options...
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