Great gas mileage with 3.5L V-6 in '04 Malibu

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faramir9

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Seeing is believing. I had read stories from owners of LX9-powered Malibus from 2004-06, who claimed better than 35 mpg highway.

I was skeptical---then came last weekend, when the boss and I took a long road trip in her '04 Malibu LS. It was roughly 800 miles overall, in three legs: 300 miles all highway going out and coming home, with 200 miles of mixed driving around our destination area in between.

I pumped up the tires by 2-3 psi, set the cruise control at 60-62 and shoved off. When we filled up after the first leg I was pleasantly shocked to see 36 mpg. The middle leg of mixed driving was about 31 mpg....and just to prove the first leg was no fluke, the third leg coming home was also 36 mpg. Total average mpg for the trip was 34.9. Would have made 35 had we not got stopped for an hour coming home behind a bad accident.

Think I like this engine. Fairly smooth, fairly powerful, great mpg....
 
My commute was about 75 miles of rural highway with very little slowing down each way. I used it for work only and kept speeds around 60 mph. In the summer I could get 38-39 and in the middle of Wisconsin winter I would get about 31-32. Of course, this was all it ever ran...about 750 miles of commuting and another 100-200 miles per week going from the office to jobsites, 45-50k per year from 2004 until about 2009. My average overall for that time was about 36 mpg. It always saw 100% gasoline, no ethanol, and I ran M1 0W-30 until the OLM said 5-8%, generally about 11k miles in the summer and about 8k miles in the winter.
 
We get 33-35mpg with the wife 05 with 112k on the clock. Do your friend a favor and tell her she can install a cabin filter in the car even though the car did not come with one. Just get one that fits a 04 cobalt. You will be breathe easer on long trips with her.
 
It's a little known fact that sticking to 55-60 MPH results in improved MPG.

The problem, as I see it, is that one can waste an awful amount of time on a 800 mile trip going 55 vs 80. 4.5 hours in fact, all to save roughly 7 gallons, or about $21-$25. My time is worth more than $4.66 per hour.

As a pilot, we perform these calculations regularly. Then determine what fuel burn is acceptable for the trip. Even with expensive Avgas and 10-15 gallon per hour consumption, it's not often we slow down to save fuel. The additional time travelling is costly in other ways.
 
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I always like that series of 60-degree pushrod V6's from the General. Light, compact, and economical. It was called the High Value V6 for obvious reasons. Then came the High Feature V6 with a large amount of power, but it's not nearly as economical.
 
Originally Posted By: Cujet
It's a little known fact that sticking to 55-60 MPH results in improved MPG.

The problem, as I see it, is that one can waste an awful amount of time on a 800 mile trip going 55 vs 80. 4.5 hours in fact, all to save roughly 7 gallons, or about $21-$25. My time is worth more than $4.66 per hour.

As a pilot, we perform these calculations regularly. Then determine what fuel burn is acceptable for the trip. Even with expensive Avgas and 10-15 gallon per hour consumption, it's not often we slow down to save fuel. The additional time travelling is costly in other ways.

I think for shorter trips, many people go 80 to save no significant time, but do use significantly more fuel than they would have by leaving 3 minutes earlier and doing a relaxed 65...
Unlike time, small quantities of money can be accumulated into a significant amount.
 
Yep, we average 18.7 ish in the Uplander. Its primary use is transportation to work which is a mile or so away, and running errands around town. I got it up to 29 MPG on one trip.
 
Originally Posted By: Cujet
It's a little known fact that sticking to 55-60 MPH results in improved MPG.

The problem, as I see it, is that one can waste an awful amount of time on a 800 mile trip going 55 vs 80. 4.5 hours in fact, all to save roughly 7 gallons, or about $21-$25. My time is worth more than $4.66 per hour.

As a pilot, we perform these calculations regularly. Then determine what fuel burn is acceptable for the trip. Even with expensive Avgas and 10-15 gallon per hour consumption, it's not often we slow down to save fuel. The additional time travelling is costly in other ways.


Fair enough, but we were in no rush. I refuse to rush when on vacation, even a brief one with lots of driving involved. Learned that lesson over the years, after too many "relaxing" trips and weekends turned out to be more work than work is.
 
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Originally Posted By: IndyIan
Originally Posted By: Cujet
It's a little known fact that sticking to 55-60 MPH results in improved MPG.

The problem, as I see it, is that one can waste an awful amount of time on a 800 mile trip going 55 vs 80. 4.5 hours in fact, all to save roughly 7 gallons, or about $21-$25. My time is worth more than $4.66 per hour.

As a pilot, we perform these calculations regularly. Then determine what fuel burn is acceptable for the trip. Even with expensive Avgas and 10-15 gallon per hour consumption, it's not often we slow down to save fuel. The additional time travelling is costly in other ways.

I think for shorter trips, many people go 80 to save no significant time, but do use significantly more fuel than they would have by leaving 3 minutes earlier and doing a relaxed 65...
Unlike time, small quantities of money can be accumulated into a significant amount.


This.
My longer roadtrips are exactly the time I want to save... time! 75 mph and burning more fuel is fine by me, when we're driving 4-7 hours usually. Shorter trips around home during the week or weekends, 65 mph and 10%+ fuel savings without a large impact on lost time.
 
Originally Posted By: A_Harman
I always like that series of 60-degree pushrod V6's from the General. Light, compact, and economical. It was called the High Value V6 for obvious reasons. Then came the High Feature V6 with a large amount of power, but it's not nearly as economical.


Both of our HF V6's will do 29 ish crossing the Boston Mountains between our two homes, if driven at 63-64 mph.

The '04 Jag will get low 30's under the same conditions, the '94 Jag ... mid teens, LOL.
 
Not only do those GM 60 degree V6 engines (which have been sold in some form or another, since the 1980s and perhaps even earlier) hold their own fuel-efficiency against the relatively modern designs, but if you see my "40k mile OCI" thread, they are remarkably easy on oil as well.

I drive a car with a similar engine from the early 1990s, and its numbers are similar to yours -- low-mid 30s. Did a 10 hour trip once at 45mph (ie: the speed at which my transaxle's torque converter locks) once and was into the low 40mpg range on flat land.

Also did a few hours on the I-94 west of Minneapolis at ~90mph and MPG really didn't drop below 25.
 
^^^ Very true. Todays modern engines seem overly complicated for their return on investment compared to the older V6 pushrod engines from the 90's and up. The designers of those older engines did a great job at the time for power, efficiency and durability. The Impala in my sig is getting almost 28mpg HGWY right now. Gasket problems fixed, but design wise was very good. Darn CAFE on the newer stuff
frown.gif
 
Yeah it must be today's emissions requirements for the reasons cars aren't getting that great of fuel economy. My '97 Camry 2.2L got 37 mpg at 60-65 mph and 33 mpg at 80 mph.
 
Only problem is driving 60 MPH on highway with traffic will get you run over.

All my cars break 40 MPG at 60 MPH, but I stay in fast lane to avoid tailgaters.
 
I took a 300 mile trip to Boston a couple weeks ago and got 39.5 mpg in my Corolla doing about 75-85 the whole way. Getting reimbursed as business expense at about 55 cents a mile. Whatever the current IRS rate is. Better than flying or the train.
 
Originally Posted By: IndyIan

I think for shorter trips, many people go 80 to save no significant time, but do use significantly more fuel than they would have by leaving 3 minutes earlier and doing a relaxed 65...
Unlike time, small quantities of money can be accumulated into a significant amount.


Certainly, one only saves a minute going 80 v 55 on a very short trip (about 4 miles) .

Put another way, 80 v 55 saves you more than a minute every 4 miles!

However, it's incorrect to look at that minute as worthless.

Over the tankful (300 mile range) , 55 v 80 adds up to 2 hours additional time behind the wheel. Again, my time is worth far more than $4.66 per hour. If you burn a tank per week, you've freed up 2 hours free time by going 80. Over a year, that's 4+ free days!
 
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The 3.9 in my mother's 2006 Impala will return similar MPGs when driven conservatively. Plus it will get up and go when kicked hard enough.

Don't know how GM did it with those Impalas, but they really had a good combination of power and fuel economy. Just hope that your trans doesn't go TU.
 
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