gas milage

[Guest Gp crazy]

Well i have been keeping track of my MPG's since we got the car For a car that weighs 3385 8) I think 23 mpg is good

 

going to try a few things to add more MPG'S after i fix a few oil seals that leak , a falty water pump with bad bearings

 

1

change motor oil to synthetic

 

2

change tranny fluid to a synthetic

 

 

3

get a under drive pulley

 

i will let you know how things go later on

[sonyman87]

carfull with the transmission change over..! do a quick search here about chaning to synthetic on a transsmision.. its not always a wise idea!

[gimp19]

I jsut found out yesterday that my Formula gets better gas mileage then the Cutty :shock: I was getting about 19mpg vs. 17 in the Cutty How does that work?

[godofthunder]

engine in CS has to work harder to move the car somewhat.

 

i get about 20MPG

[GutlessSupreme]

I figure I get about 17.. but that's with me just about flooring it after every stop.

[jeremy]

~27 on the highway ~20 city.....I drive on the highway 85-90% of the time.....

[99RegalGS]

I get 30 mpg going 75 and it surprizes me that you guys get lower gas milage eventhough I have a bigger engine. :?

[GutlessSupreme]

god damn I wish I got 30. Most of my driving it city though, and having a heavy foot doesn't help..

[azxr]

I get 22 city and between 30-33 highway. Everyday driving I get between 27 - 29 (Highway/county roads/city).

[IL_pilot]

I get 30 mpg going 75 and it surprizes me that you guys get lower gas milage eventhough I have a bigger engine.

 

HOW?! What kind of RPM's are you turning to get that milage? I've got 75,000 on mine, with (pretty much) the same engine, (hell, we have darned near the same car) and the best I've been able to get is 24 highway at ~70mph. Been averaging 21mpg mixed 70/30 higway/city driving like a granny.

 

BTW, running Mobil1 5W30 and tires are inflated to 32psi. New plugs, wires, air and gas filters. Maybe I should get my alignment checked, it's either that, or my rear-end squat is making it draggier, or it's this crap gas we have in chicago (what good is the 10% ethanol in my gas if I burn 10% more of it just to go the same distance?!)

 

[99RegalGS]

HOW?! What kind of RPM's are you turning to get that milage? I've got 75,000 on mine, with (pretty much) the same engine, (hell, we have darned near the same car) and the best I've been able to get is 24 highway at ~70mph. Been averaging 21mpg mixed 70/30 higway/city driving like a granny.

75 mph is almost 2100 rpms on my car. I averaged 29.7 mpg on a 300 mile trip last summer and I was doing at 75-80 the whole way. You have a 3800 correct?

[IL_pilot]

Yeah, series I 3800. Does yours have the electronic trans or the older style? I pull around 2100 or so at 75 too.

 

Could be my driving though; mostly highway, but it's Chicago highway; back and forth between 55-75 might be doing it. I commute 25 miles each way to work everyday, almost all urban highway. I remember my Grand Am would get around 24-26 highway in Illinois, but when I drove to NJ, I averaged around 29, with a high of 32 once I got off the ethanol crap we have here, so maybe that's it.

[99RegalGS]

Yeah I have the electronic trans. I think you're right about the Ethanol in the gas.

[optimusprime]

I was getting about 24mpg in my '91 GS with about a 50/50 City/HWY mix up until recently. I'm down to about 19MPG now with no change in driving style.

[dbtk2]

I get about 14mpg city (its the way I drive), and 30mpg highway in my STE.

[Mint Euro92]

We took a 500 mile trip today 250 there & 250 back & got 34 MPG Miami Fl to Orlando Fl & back

[ShockTherapy]

my GS got about 13 MPG, of course it never ran right, and $2,500 worth of headachees later, the tranny blows, and i get stuck with a chick car, at least i get 32 MPG now.

[Guest Gp crazy]

my rpms are at 2500 at 70-75 but some times it can get lower it can get around 2100 rpm or so AIR TEMP seams to have a big play in the whole system when it's 50 or better it runs better also i have changed the air cleaner to K&N and added a FUEL boss (i.e. it's a mangnet that goes around fuel line on the feed side ) it say's it going to add 10 % fuel milage so far it has worked the next thing is to change the o2 sensor. i never did it on the first time tune up. :dammit:

as far as trans. fluid i will have it changed at a tranny place because i want them to fix the speedo also. the speed sensor is reading right but the speedo is 20 mph off 65 = 85 i though it was rims were wrong but they are the right size. 215-60-16 1990 GP STE 130,385 and counting

well off to work now bye

thanks jeff

[IL_pilot]

Yeah I have the electronic trans. I think you're right about the Ethanol in the gas.

 

Hmm, I'm pretty sure I have the 4T60, not the 60-E. Checked today, turning ~2000-2050 at 75 mph. Maybe that's it...

[99RegalGS]

The 3800 got the 4T60-E in 93. I'm almost povitive that the gear ratios are the same between the 60 and the 60-E, and even the 65-E. So that won't make a difference. The only differences are the Final drive ratios. Now I know my car has a low preformance 3.06 gear ratio compared to the 3.33? and 3.43 that other W-body engines had with the 60/60-E. You probably have the same one as me.

[AWeb80]

engine in CS has to work harder to move the car somewhat.

 

i get about 20MPG

 

Damn, in my GP, I can get 23-24 consistently.....and thats with 101400 miles on it.

 

About a month ago, I drove it on a all highway trip....driving 65-70 the whole time and got 28 MPG

[89oldscutlass]

I get 30 on the highway but im lucky to get 20 in town.

[Heza]

in the '94, the 3100 gives me about 20 city and 30 highway.

in the '96, the 3.4 gives me about 14 city and 24 highway.

 

i gotta work on the 3.4s efficiency a little bit i think.

[sl3196]

I get around 28-30 on the highway. Thats with 137,000+ miles!!

[91CutlassSupremeCoupe]

Does your Firebird have a 6 speed?

 

Manual transmission and major overdrive 6th gear. That's why you have that kind of mileage. If Cutlass' had an F-body 6 speed mated to a 3.1, they could get damn near 40mpg like a Sentra.