So when I first bought my '83 245 off the lot a year ago, I was running an average of 230 miles to a tank of gas (translating to about 17mpg, since I hadn't pushed my tank all the way down to dry yet). Nowadays I'm amazed at the distance I can go. I just took it on a trip and managed to pull out more than a half thousand miles before I had to use the reserve tank in my trunk, meaning 34mpg (nearly hybrid quality)!

The secret? Simple. My three F's of great mileage:

1 - Be like a (F)eather on the gas pedal. And I DO MEAN LIGHT! It takes me at least a full minute to accelerate to 40mph. Sounds crazy, but believe me, it pays off. Why jackrabbit yourself over to the next red light when you can just as easily turtle your way there? And yes, FOLLOW THE SPEED LIMIT!
2 - Drive (F)ifty on the freeway. Yeah, the minimum's supposed to be 55, but seriously what cop is really gonna be checking for those going 5 under as opposed to 5 over? The "disadvantage" is it takes twice as long to get places as opposed to driving 100 like I used to when I was 18. :)
3 - (F)uck what everyone else thinks of your driving. That's right, turn down that rear view mirror and turn up the stereo and forget about those people behind you who are desperate to drive their SUV's and monster trucks like racecars. This is by far the hardest rule to get used to, but once I did, I found myself appreciating my good stereo system even more and actually enjoying taking my time to get places.

Of course there are other things that benefit mileage too, like using premium gas (with the mere 25 cent difference between regular and premium still around, it more than pays for itself in the extra mileage I get) and a bottle of STP injector cleaner, maintaining the car well (changing fluids and filters when appropriate, etc.), and (if you have a manual) not over-revving the engine. Trust me, you WILL see a difference of at least 100 miles a tank if you are a stickler for the rules. I've found having a turbo gauge on my non-turbo engine works well in letting me know how efficient I'm being on the gas pedal. I pick a low spot and basically don't ever let it get above that line (except on hills of course).

But there are a couple questions I have for any experts out there who know more about the effects of certain tactics on the wear and tear on the car, and I'll post them in another thread. Oh, and if any of them also have comments, like I shouldn't be doing this or that to the car for these reasons, please let me know because I certainly don't know all the lasting reprocussions of low-revving and STP every tank. Thanks! Happy driving!
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-jp ('83 245 DL, 210k, 4+OD, no A/C, piss yellow color - but hey, it's got a computer in it)

Feather light on the accelerator, should be "steady throttle".
I drive several hundred miles a trip (Interstate, and city ) three / four times a week, and get a consistant 29.5 to 31.5 mpg, at 5mph above posted (65). I have found that at 75-85 MPH, with a steady throtle, I can up that to 5 additional miles to the gallon. What kills my MPG is having to adjust throttle for SLOW MOVING TRAFFIC, or for interuptions in the traffic flow. Such as the driver who sits in the left lane, and interupts timing for vehicles that need to pass a slower vehicle. In town (city) driving with a steady throttle is a simple matter of not rushing to the next "Red" traffic light, time forward movement for the "Green". Each time the brakes are used, more energy is required to get back to "steady throttle".

The true secret for better gas mileage are the three "M's"....Momentum, Momentum, Momentum. Interuption of which requires more energy to reestablish.

As to inflating tire pressure to an "uncomfortable ride".......also inflates the loss of vehicle control in dry or wet.

As to you're #3 F...."turn down that rear view mirror and turn up the stereo and forget about those people behind"....is the most dangerous action that one could do. As a responsible, on the highway, vehicle driver, one should be constantaly aware of their immediate surroundings, and anticipate events unfolding before them. Once behind the wheel of a moving vehicle one becomes a member of a moving community, complete, with responsibilities to other like community members. At the same time, that driver actually becomes the guidance system to a very lethal wepon. Think about it.

Achieving "good gas mileage" isn't about driving slow. If that were the case, you're best mileage would be not to drive at all. Which, come to think of it, is what I suggest you practice.
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84, 242GLTi, 167K, 4+OD, still in rehab; 89, 245 DL, 309K, M 47, daily driver; 93, 245, auto, 167K ; and other toys.

I completely agree with this post. The 3 M's are where it's at.

If anybody actually reads their Volvo owners manual, there are specific helpful hints to achievie the best fuel economy, and I trust the experts at Volvo to know better. They state that you don't have to drive slow to get good mpg, but get to your cruising speed in top gear as quickly and as safely as possible, then maintain the cruising speed as much as possible. This means rev through the gears while shifting at low rpm's as quickly as possible. For those of you who have the up arrow shift indicator on your 5-speed as I do, it will instruct you to shift at relatively low rpm's (< 2200), pushing the car while the engine is in the torque band of the rpm's. Do this while nearly flooring the pedal and you'll get to highway speed more quickly as well as saving fuel.
Like the truckers out on the open road, moving the vehicle while allowing momentum is key to saving fuel. Anticipating hills while bringing engine rpm's up before the climb to maintain engine rpm's is a big fuel saver. Keep the rpm's constant (as well as engine vacuum) but not necessarily the car's speed. Dropping the speed a few mph up hill, and letting the car's inertia carry it down the hills rather than the engine power helps, too (but don't let off the pedal!). As truckers do, the vehicle weight and momentum will work for you while at much higher speeds than 50 mph. On the open road you find the magic speed is somewhere between 65 and 75 mph, or speeds lower than when wind resistance and aerodynamics take any significant effect, but high enough to allow momentum to carry the car up a portion of the hills or along the flats.
The trucking folks lobbied for years to have the speed limits increased for just this reason, and these guys drive for a living and mpg is their major cost/expense factor to making a good living out of it, so I place faith in their ways of driving. Besides I've drivin across the US so many times keeping pace with them, I know it works. Drafting also works really well, which is something they also do, but I suggest that if you attempt to do that you better gain their respect for your driving skills before you try to do that, and driving 50 mph in a 70 zone will piss them off (as well as everybody else on the road), not to mention get run over in your Volvo and worsen the reputation they already have of people who drive Volvo's.

I would use Techron not STP, every 4th tank, and premimum gas. Your car will be much happier.
Keep the tires inflated on the high side but not over inflated for the load. Don't go to 40 lbs unless you have a lot of weight. I usually run the H rated tires at 36 psi unloaded for best MPG. If your running S rated tires, don't go over 32 psi.

My car has gotten the best ever mpg at 87 mph with a good load, 2 people, luggage and the dog, windows up/ A/C on cruising across West Texas on the flats, got 31 mpg. The windows down can significantly worsen fuel economy, especially for the poor aerodynamics of the 240.

The biggest source of danger on the highway is a speed differential. Driving 15 mph UNDER the normal traffic flow is as dangerous as driving 15 over. Maybe more so, as you've mentioned you turn your mirror down.

If you're going to drive that slow, at least use your flashers!

I don't think your engine suffers at all from running at lower RPM. There's no need for that STP snake-oil in every tank though. I would wonder if it makes things worse.

Idiots that drive like old ladies cause accidents but rarely get hit themselves, you realize that driving 50 in a 55 is wrong when the normal traffic is flowing at 65 or so. All for a few selfish pennies in your wallet, sheesh get a life. What you are doing is about as incomprehensible to me as the habit of those who slow down and/or stop on the acceleration lanes, dangerous and frustrating for the cars all around while the idiot doing it is in some other world.

Idiots that drive like old ladies cause accidents but rarely get hit themselves, you realize that driving 50 in a 55 is wrong when the normal traffic is flowing at 65 or so. All for a few selfish pennies in your wallet, sheesh get a life. What you are doing is about as incomprehensible to me as the habit of those who slow down and/or stop on the acceleration lanes, dangerous and frustrating for the cars all around while the idiot doing it is in some other world.

Get either rare economy gauge or common turbo gauge connected to the manifold to monitor feathering habits and road condition effects.

You forgot the fourth - F - which is: Fill up the tires with air and check often.

sounds like highway, similar to my driving situation.

I also have my tires hard with air, uncomfortably so.

The other thing is when I am at a light, I know all the "times", so I shut off the car when stopped; mine starts very well, YMMV.

I do a fair bit of coasting too, but I know my route and the traffic very well.
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Stef (81 245 B21A SU M46 3.91) 327000km my volvo pages

True that. I suppose I thought of that as part of the general maintenance plan, but it would make for a nice addition to the F's. :)
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-jp ('83 245 DL, 210k, 4+OD, no A/C, piss yellow color - but hey, it's got a computer in it)