Gas mileage help, please read

[crm391]

I drive a 2000 chevy metro 1.0 5 speed. It is driven 99% of the time at 70 miles an hour for 2 hours to and from work 1 way, I am averaging 36 miles per gallon. Is this low, I here that there are others getting 45 plus mpg. I have completely gone thru the car, plugs, wires, cap, rotor, belts, hoses and synthetic oil and a 10 degree cam sprocket from 3tech, brakes,rotors, cv axles,struts,ect.... I have also installed new 195/80/13 tires to give me an effective final gear ratio of 4.10. car actually has 4.39 with stock tires. I have checked for vacumm leaks and found none. The car does not have the fuel evaporative canister under the hood, the lines were plugged off, this does set a related code in the computer. My question is will the lack of the tank prevent the car from going into lean burn thus giving me only 36 mpg. What is lean burn and how do you tell if in fact it is going into lean burn. Another thing is with the air conditioner on, the mileage has actually gone up to 38mpg, any suggestions will greatly be appreciated.

[Metromad]

Slow down! I get 45mpg; but then I only drive 60 mph, tops. I don't try to power up hills, preferring to use a steady pedal where possible. These cars were never meant to be speed demons. They do one thing and they do it really well if you drive them properly, get good mileage. Remember, the statistics show that for every 5mph over 45 that you drive, you lose approx. 3 to 5 percent mpg depending on the drag your car experiences. You can try re-installing the canister, ebay has them but I would be wary of those. Try your local parts house. Will it help? Not sure since the canister's main function is to keep fuel vapors from entering the outside air. But its possible.
I would recommend overhauling your driving style first before you put any more money into the car. Don't: roar away from lights, come flying up to lights before stopping, put your foot to the floor going up hills, warm your car up for more than a minute before driving, leave car idling for more than a minute, and on and on. Do drive sensibly, keep the car in tune (sounds like you have done that one), keep your tires inflated to top pressure listed on the door frame, keep oil changed regularly, and on and on. My experience has been that most people buy these cars with an unreasonable expectation that they will get 50mpg no matter what. Very unrealistic. You have to sacrafice a little, and if that means not keeping up with your neighbor on the road, it will mean passing him at the gas station!

[atleastitsnotaford]

On a recent trip to Dallas ( 200+ miles) in my '95 3cyl 5speed, I was tearin a** 70-80 mph, passing ppl, trying to get there in a hurry and got 35 mpg.
On the return trip, I cruised along at 60-65, slowing down going up hills speeding up going down them. I got 56 mpg on the return trip. (I know some sceptics will say nuh uh, that's too high, but keep in mind this was one trip, and factors like air temp, wind speed and direction will affect mileage on any given day.)
Either way, the point is slowing down to where the car was meant to run will give you the mileage it was meant to get.

I you want to run it faster, build it to go faster, you won't get as good of mileage as going slower, but you can still get better than that.
BTW I normally get 38-42 mpg mixing in town with highway.

[dale]

Howdy, I normally get 38-42 mpg mixing in town with highway driving also. I have a 1985 Chevy Sprint G10 Carb'ed engine 5 Speed Tranny....

I have done the fixes that crm391 did to his car also..

Just driving it at 60 mph, not faster will get the above MPG just like Metromad gets.....

[Aviator 902S]

Interesting... just before the engine in my '95 Firefly cratered I was getting 49 miles per (imperial) gallon (around 43 miles per U.S. gallon) while driving mostly highway speeds of around 70 mph.

This included the occasional (but becoming more frequent) bogging down on long hills due to a plugged cat. I'll report back after I've rebuilt the engine with updated figures.

In past experience with this and other cars, I've found that you CAN put it on 70 mph and still get close to top mpg, as long as it's all highway miles with few steep hills, and as long as you don't max the revs between shifts. But fuel economy drops off exponentially above say, 75 mph, no matter what car you're driving.

[crm391]

Hey folks, I work in Miami, I leave the west coast of florida at 4am to be over in Miami at 6am. Its florida guys, flat as can be, as far as driving 60, I have done the trip at 60 and 65 with minimal change and recorded 34-35 mpg, no improvement. I am begining to get info on the throttle position sensor and how to adjust it, will keep you posted. Does anyone know how we can tell if this car goes into lean burn mode?

[atleastitsnotaford]

A buddy of mine was commuting about 70 miles round trip in his '93 metro. Getting better mileage than his truck, he was more concerned that the car had no balls. It would top out around 70 going downhill. He was getting about 35 mpg regardless of how he drove it. As it turned out his father-in-law had set the timing wrong, and it was retarded to about 2 degrees after TDC. His car now tops out close to 90, and gets around 40 mpg. (I still think he's driving faster than he sais to get that)

[Aviator 902S]

One thing that hasn't been mentioned here yet is roll resistance. If you're running 185 tires of any height you'll pay a little more at the pumps for this very reason. I've found on my cars that the skinnier 145 and 155 tires (though not as aggressive-looking) return better fuel numbers, particularly at highway speed. And as long as you're not taking corners at break-neck speeds traction isn't an issue either.

[atleastitsnotaford]

I'm running 175-70-r13 tires. I like driving like it's a go kart, so............. Any who, yes the skinnier tires will make a big difference ( all else being equal)

I just now re-read the original post. You say you got better with the A/C on? That boils down to only one answer. Wind resistance. If you've switched to a 195-80-r13, that's a lot taller than stock, and will throw your speedo off. Have to do some math that I'm too tired for right now to tell how much, but could be close to or more than 10% Meaning you're doing 77 when your speedo says 70. If your getting 36 mpg @77 mph with that car, you're getting near the edge of physics. You'd probably need a B.S.F.C. of less than 0.40 to do that.

[Aviator 902S]

I've just ran the first full tank of gas through my '85 Sprint. I know it was a full tank because I filled it to the brim and then ran it completely dry on purpose. The fuel gage is broken and I needed to know what kind of range I'd have at a typical highway driving speed of 75 mph. (And yes, I did carry a spare 5-liter jerry can of fuel with me).

The trip-odometer read 491 km (305 miles) when the engine finally sputtered and died. I then drove the 2 miles to the gas station and it took 27-1/2 liters to fill. So this gives a tank capacity of just a titch over 32 liters, which = 7 Imperial gallons. This translates into 8.41 U.S. gallons.

305 miles divided by 8.41 U.S. gallons = 36.3 mpg. This is at 75 mph typical highway speed, and all of this tank was used on the highway rather than city driving. Engine is in good shape and was rebuilt a few years back.

The kicker is that my '95 Firefly with its bagged oil-burning engine (and clogged cat, which limited cruising speed to around 65 mph) returned 40.1 miles per U.S. gallon.

[atleastitsnotaford]

I just made a jaunt over the state line with my hyundai sonata yesterday. It's got a mpg display on the dash. Won't give you real time mileage, but will give an average from the last time it was reset. I reset it at 70 mph, then racked it up to around 110for a few miles, and the gauge plopped down to 16.8 I slowed down to around 80 and it crept up to 21.1 My normal driving style hovers around 65-70 on this same trip, and the car gets around 31.2 when I keep it in that range with a little in town driving.

Moral of this story: drag increases exponentially with speed, and the new sonata's are f***ing fast. The '06 and '07 v-6 models top out at like 160 mph!

[atleastitsnotaford]

Just a tidbit from my last two trips in the metro. I'm getting around 36-38 mpg with a 3 cyl five speed! I am impressed with these numbers as my cruising speed has been between 85 and 90 mph!

[95basemetro]

WELL, fellows I have just figured up my mileage for the four months of Jan, Feb,March, and April of this year. I deliver takeout food 3 (sometimes 4) nites per week and almost all other driving that I do ( I have other vehicles to drive also) so my driving is almost all village type short trip useage, ie to the grocery store, to the shopping centers and Home depot etc. My mileage just figured to 42.226 for the entire 4 months, over 5000 miles in these 4 months, so as you can see I am not a particularlly high mileage user, but I think that this is GREAT, as my 95 Chev 1/2 ton 4wd gets 14 at best, my toyota tocoma gets 18/19 under the same conditions, both trucks have automatic.

[atleastitsnotaford]

that's pretty damn good for all in town driving.....hell that's not even all that bad for the chevy all things considerd.

[gone_postal]

I know- and his pickup is a '95. That's pre-vortec, and they don't do so well. My '96 is a vortec, and I got 24.3 highway out of it, but the town mileage sucked butt.
My Metro is running 42, 43 overall mpg dependably. I can't beat it hard enough to drop below 40 now. A cap, rotor, plugs, wires, and synthetic oil made a HUGE difference in its performance, and then brought another mpg or two. For stuff you do anyway.
Mine was all carboned-up when I got it and 100 miles a day round trip is limbering it up and making it run better and harder too. I still have problems with bucking the wind, but I think all metros do...
And it's still afraid of trucks!