My 2001 etc will only get 24 miles per gallon on the interstate. The car is still under warrentee and the Cadillac dealership cant find any problems. My car runs 1900 rpm at 60 mph. is this normal? I have 46k miles on the car.... I owened a 97 esc that would get 30 miles per gallon on the interstate. What kind of mileage do you get?
[:@]Dale in Georgia.

 

My gas mileage is the same in my 98 Deville. I usually drive around 120 KPH so 75 MPH or so. I thought it was pretty good. Your RPM's sound about the same as mine too of course it all depends on axle ratios.

 

When I said I got 24 mpg on the interstate, I was only driving 60 mph of flat terrain. My 97 ESC would get 28/30 mpg. driving that same speed on the interstate. I know that the ETC has25 HP. more than the ESC, but I did'nt realize thatthere would be a big differance in mpg.I had found an internet site that advertised a device that you install on the engine that boost thempg a few more mpg. Has anyone tried something like this and does it really work?
By the way,my 97 ESC was rearended this summer and I had to let her go to her final resting place inCadillac heaven. I liked the Eldorado so much, I went and bought a 2001 ETC last month. She's still under warrantee and in tring to get her in tip top shape. Matter of fact I had the Cadillac dealer replace under warrantee, the rear window trims on both sides whereI have noticed a lot of other Eldorados had the same problem bulging out out from around the side windows and rear glass.
Dale in Georgia

 

You know tire pressure affects fuel economy as much as anything else. There is usually 1 or 2 mpg in the tires if they are under inflated, plus bad alignment creates drag as well. You can even over inflate the tires a bit which reduces rollling resitance. By my way of thinking I don't like putting engine add ons to my everyday car that I rely on. Little things will help the mpg, clean air filter, new plugs and wires, what we used to call a tune up. I'd be interested to know wht your final drive ratio is, mine is 3.11 which is good for acelleration but the OD kicks in and helps out on the highway. I think the ETC may have lower gears than the ESC too since the Deville Concours ratio is 3.71 vs my D'elegance at 3.11 and the HP differential is the same 25 HP. I honestly don't think the HP difference makes a diffference because the lower HP motor actually makes more power in the low RPM range and the higher HP motor makes more at high RPM's which you would never really be running, at least I hope you don't run at 6400 RPM!

 

You were right about the tire pressure, I checked them last night and they were reading 25psi..... I raised the presure to 35 psi. and i gained almost 4 miles per gallon. Usually I keep an eye on things like that but I just purched the car and the owner said it wasready to drive to California (for me that would 3000 miles). Besides the tires looked well inflated. So much for just looking. Thanks for reminding me. I dont know what my final drive ratio isor even how to look it up.These are the gear ratios listed for the transmitionin mycar.Hydra-Matic 4T80-E




First:

2.96


Second:

1.63


Third:

1


Fourth:

0.68

 

Here is the information I researched on your ETC from GM Canada Archives. I put the link here as well, just a ton of information on your car, you may want to print it out.

http://media.gmcanada.com/ca/gm/en/p...1Eldorado.html

TRANSMISSION4-Speed Electronic Automatic withOverdrive
Gear Ratios 1st 2.96
2nd 1.63
3rd 1.00
4th 0.68
Reverse 2.13
Final Drive Ratios 3.71

Of course everyone who reads this today will be checking their tire pressures but to get4 mpg, that is fantastic! Glad to be of assistance.

 

If you want give this a try: Replacing your catalytic converter with
a magnaflow cat also a high flow air filter, worked wonders for me

 

ALL IS TRUE....99 STS, WITH TIRE PRESSURE AT 40's I'LL GET AROUND 27/28 MPG. I HAVE LOWERED THEM FOR WINTER DRIVING AND GET 23/24 MPG. dlschore...welcome to the forum dude, see ya round
rickyd