honest mpg of 4.9 city driving survey

Short trips, traffic lights...could be.

My 4.1 (same family of engines) consistently gets 16.1 around town in summer, 14.2 winter. On the highway, 26.4 summer, 21.5 winter.

The wide variance is caused by a low hp, low torque V-8 straining to get a heavy car moving in stop and go traffic. Once it's rolling and stays that way, inertia (and the VCC) kicks in.

MY mileage right now is horrendous. Trying to narrow down what it could be. Working on a few things as time allows. (any input here appreciated) Right now, Im about 8 or 9 mpg...sickening....but car runs like a top which really frustrates me....Not that the car running good frustrates me...If it was running like crap id expect the poor mpg.

9 to 12 here in Ky. in the city. 10W30 synthetic. Not very good but on the highway it gets 22 to 26.

85 Deville with 4.1: 15 city (lots of stopping), 26+ highway
92 Seville STS with 4.9: 13 city (lots of stopping), 23-25 highway

4.9 on 5 mile trips with a average speed about 40 is averaging 17-18 mpg with only a few stops. Heavy traffic on the same routes can push me down to about 15.

Havent taken it out on a highway trip

Update:

I've been driving about 110 miles roundtrip to a consulting gig that I've had for the past 5 days, and have filled up twice with my 92 STS. You won't believe the results (I didn't!): 27.2 mpg on my first fill up and 27.1 mpg on the second. This is ACTUAL mileage--not what the trip computer said (which was actually about 2-3mpg less than what I actually got).

These figures reflect about 70% highway travel at 70mph, 15% street travel at 55mph (with few stops), and 15% street travel at 35mph with lots of stops.

What amazes me even more is that these numbers are so high given the fact that my converter lock up solenoid is inoperative (should get better mileage if it was working, but I'm not about to have someone pull the trans apart--don't trust those guys).

My calculations were all from reading the computer, I havent double checked it manually yet. I may do it now since I always reset my trip whenever I get gas, I just dont always top it off, But I could go for 27mpg lol. Must be nice

About 14.8-15.4 MPG in city in summer
13-14 MPG in city in winter

On the highway, I've never taken it on a real good trip in the summer, all of the good highway drives I've done are usually in the fall or spring, but during that time, I've seen anywhere from 21-30 MPG at 70-77 MPH. No shit. I've only seen the 30 MPG once, but I suppose the average is about 24-25

I'm going to Des Moines tomorrow and I'll fill up right before I leave. I'll post my results afterwords. I'm expecting 26-27 at a steady 70-75.

I get 17-18 mpg city with my 1995 4.9 litre Deville in spring/summer,14-16 mpg city in winter-------25-30.5 mpg highway depending on wind conditions.I got the 30.5 mpg highway twice last fall,but i had a good tailwind both times.

My 1992 ETC is getting 16-18mpg city (which is why I'm selling it, the gas mileage is killing me)

ah2k6 said:

My 1992 ETC is getting 16-18mpg city (which is why I'm selling it, the gas mileage is killing me)

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What are you going to replace it with, 18 seems pretty decent for city, Alot of newer/small cars only get mid 20s and it would take alot of driving to make up the difference

Just got back from up north and a 500 mile round trip with my 85 Coupe Deville. Average 26.5 mpg on the road (mostly highway). These engines really get excellent mileage if in good tune, considering they're V-8 engines, and considerably larger than what's in today's cars (albeit less powerful).

behind-bars said:

What are you going to replace it with, 18 seems pretty decent for city, Alot of newer/small cars only get mid 20s and it would take alot of driving to make up the difference

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Fair enough. I was just getting frustrated with the car but it's financially smarter for me right now to keep the car, and just suck it up for the gas mileage. I was driving my dad's Sunfire beforehand, which was getting around 30mpg city, so it was an adjustment thing for me.

behind-bars said:

My calculations were all from reading the computer, I havent double checked it manually yet. I may do it now since I always reset my trip whenever I get gas, I just dont always top it off, But I could go for 27mpg lol. Must be nice

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Filled up today, 11.3x Gallons with the trip at 202.x reset last fillup
Took 23 days to run the 202 miles, 5 mile commute to work at avg speed of 40ish, top speed of 55 (60 sometimes, but 55 zone):canttalk:


Works out to 17.8x which is dead on with the computer read out. I found logs where I confirmed getting 18.5x mpg about 1 year ago, not sure why the drop.

Im getting 17.4 w/ city driving. Not a whole lot of stop and go but I baby the hell out of my 4.9. I will coast a good 500ft before stopping at a light if I can. I usually have a lead foot but the last year or so I have laid off of the pedal since gas prices are so high.

-Jp

14 - 16 mpg city. 1994 DeVille

I suppose in about the 15mpg area in the city but highway ill get 25.

Chad and I on the way to the National meet got 21 on the way there and 28 on the way back so wind and drag do come into play with these boats.

We dont get 40mpg but we get there looking good and feeling comfortable.

1993 4.9 l seville 15.8 all around 40mph on the road to my work but i drive on the freeway at night 55 mph I want to not get pulled over in the city when I go to madison or oshkosh I go 75mph to 80mph that I think is bad for fuel consumption