With that kind of gas mileage, she must be running very poorly, maybe on but two cylinders..
The real life mileage is probably closer to 30 to 40.
Do you maintain an accurate MPG log ??
Once set-up, this is easy to do...
An exhaust restriction will cut performance by maybe 10%, maybe more if really bad....
Ensure that you have the necessary 13 to 14 volts for the effective operation of the computer and control units..

Any gas leaks, maybe a locking gas cap is in order ?? - I hate those things, and maybe they are no longer necessary ..

thanks earthworm...

k all cylinders are firing,
gas log is up to date, in fact im recalculating it now
i'll look for the exhaust restriction,
and check the battery..cuz i also have subs and a radio in there so that could affect it?

fixed all gas leaks and have a locking cap just in case -still low mpg

thanks

sticking parking brake, slipping clutch, alignment way off, tire pressure way low, does this car seem to slow down really quickly when you put in nuetral and coast?

also is the check engine light on and what year is it?

the car is fine in neutral...no engine light, and its a 1.0L 3 cyl 5 speed 1991 Geo Metro...just had 2 tires replaced and rotated..clutch is fine too

Has it passed an emissions check recently (if they're required where you live?). If not, you might get some valuable clues as to the problem by getting it tested (make sure they do an "unofficial" test).

If it's getting 15 - 20 mpg, I'd think it would be smoking. Check the spark plugs to see if they're gas or oil fowled. While they're out, check the compression. I used to see a lot of metros around. A few years later I'd see a few metro mosquito foggers around. Now don't see hardly any. Leaves me with the impression they're good for fuel economy, not longevity. What year is this thing and how many miles are on it?

no smoke..all spark plugs are good, all cylinders are firing, compression is good, 155 K miles, 1991...

aftermarket muffler, subs, etc... you didn't radically change the tire size that might affect your odometer reading did you? Just a thought. You seem to be describing a car that runs and drives fine but uses twice the gas that it should, I don't think this situation is possible.

Good luck.

That's funny. Maybe earthworm is on the right track with his locking gas cap idea. Live in a tough neighborhood?

Oh this reminds me of a good story my dad told me several years ago. He worked with a bunch of jokers and one of the guys at work bought himself a new volkswagen something or other, anyway it was supposed to get around forty miles to the gallon. He drove it a few days and started bragging on how good the mileage was so the joksters began each day at lunch going out and actuallty adding a gallon of gas each day at lunch (gas was cheap then) well this went on for a few weeks and they were really getting some good feebback from the owner he was getting astounding mileage darn thing was almost free to drive so they then decided it was time, so they started siphoning out a gallon every day at lunch, they could hardly get any feedback from the proud new owner then, except that he was going to have to take it back for some service he actually wound up trading it in for another model before he even knew what the pranksters had done to him, and then of course no one would say, I don't think the old boy knows to this day what was done to him. GET A LOCKING GAS CAP TODAY

I've reviewed the posts so far on this problem and I am puzzled. Something is definitely wrong to cause the gasoline mileage to fall to half. Check for an exhaust restriction, maybe a plugged catalytic convertor. When the exhaust is restricted, the throttle must be opened more to scoot down the road at the same speed as before, the vacuum falls causing havoc with the ignition advance and enrichment. One symptom is a backup of oil fog into the air cleaner, and an oiled air filter. Continuing to run in this condition may ruin the engine, since the crankcase is not being purged as it should and the rate of oil contamination is increased.

A second item to check is the MAP (manifold absolute pressure) sensor. However, when these open the engine may start and run at idle, but will hardly run as the throttle is opened.

Those things usuaully cause some major performance problems though. Ought to be even worse with something powered by a 3 popper. He didn't say it ran any different than it has for the last 14 years. While we're speculating you can throw worn cam lobes into the mix too. That can cause it and the engine might still run smooth. Still ought to be other symptoms though.

You could connect a vacuum gauge to this engine and see what it tells you.

Pep Boys has 'em for $20.

Worn cam lobes are a possibility.
The performance loss is very gradual, the owner may never notice.

We had an old Dodge truck that MAY have had worn lobes. She was extremely smooth, easy to start, but without normal power..

Also, running a device that uses a lot of voltage, (a sub-woofer) may upset things(electrically), maybe even cause low mileage..

IMO, neither should have that drastic an effect on gasoline consumption..

And I still would like to know exactly how the consumption is being determined..

Also, it may be possible for a fuel leak to occur without detection, at least for a time..

A vacuum gauge should show worn cam lobes, along with exhaust restrictions, retarded timing, and a whole bunch of other problems.

im figuring out my mpg the old fashioned way... by writing down my miles, how much gas i put in, then how many miles when that tank is dry..simple math.

and ive checked for fuel leaks, havent found any thus far, and when i say i've checked, i mean that when i replaced the brake lines i pulled the tank off and checked all the lines. (i do all maintenance myself) and fixed any leaks then. i've torn the engine apart and cleaned it up and such when i first got it, and it had a burned valve on the middle cylinder, so i saw the cam shaft and other inner workings and theyt appeared fine...it is a 91, so i suppose the catalydic converter could be clogged from leaded gas use (leaded gas was gone in 95) and im going to be checking that either today or tomorrow

thanks for your help so far guys..

This car still should hit 80 mph, if not, do the vacuum tests, check the valve timing, maybe it is off by a tooth.
If the converter is clogged, some overheating , hard starting, and a loss of performance will result, as well as the MPG drop..

I was under the impression that leaded gas went out in the 70s.

In which country is this Geo located ??

When the catalytic converter clogged up on my truck it made a whistling sound when I accelerated, but surprisingly there was no reduction in fuel economy. I'm sure the fuel economy could have gone down if it had gotten a lot worse.

Is the economy the same even if you fill up and then just drive constantly, maybe 30 or 40 miles? This would be something I'd want to check. If it's a leak from the tank or from somewhere else that it could drip out while it's parked, you should see a big improvement in your mileage from filling it up and then just driving without giving it much time to sit.

Gasoline leaks can be hard to spot because gasoline evaporates so quickly. Sometimes the best way to see it is by looking for a really clean area. That could be an area where gas is leaking out, or dripping on to after it leaks. Of course smell is the other good way to find a gasoline leak. Does the car smell like gasoline when you open the hood while it's running?

Does the oil smell like gasoline? If so you could have a carburetor problem and gas could be leaking down into the engine after it's shut down.

FYI,
I had an '88 fuel injected Chevy Sprint (same 1.0L, 3-cyl made by Suzuki?) and used to get 40~45 mpg in mixed city/hwy driving. It had a 8-gal fuel tank, so the total range was not that great. The car ran good for about 10 years until getting T-boned by another car at 10 mph and it got totaled. If it wasn't it, I'd be still driving it.
I don't understand how there could be no change in performance of this Geo when it gets such low MPG.

The Drummer : im figuring out my mpg the old fashioned way... by writing down my miles, how much gas i put in, then how many miles when that tank is dry..simple math.
EW : I hope you do not wait until the tank is dry !! lol lol, this would be a real PITA every time.
Yes, as the cowboy says, a hard to detect gas leak can exist.
Why not pressurize the system and check her out..
Gas in the oil can explain some of it..
The engine timing must be right on - remember , IMO, she should hit 80 mph..

Posted by: earthworm (My Page) on Mon, May 2, 05 at 12:13

Worn cam lobes are a possibility.
The performance loss is very gradual, the owner may never notice.

Except for the annoying popping coming out of the carburator.
You sound like you may have worn lobes as well.

I'd love to read about the solution to this problem.
No question, with a 3 cylinder car with a burned valve, the fuel economy will take a hit, a big hit..

Hey guys i got a 1991 geo metro and i can get it to idle right and turning on my headlights makes it worse and if my fan kicks on it acts like its not gitting enough gas would someone please help me.

I had identical problem. Got a used vacuum sensor for 15 bucks at the local wrecking yard. It looks like a small domino mounted on the top of the firewall. It has a vacuum line and a small electrical cable going to it. The device (when working) senses changing engine loads (such as lights and fans, etc.) and signals the engine computer to adjust the engine speed to keep it constant under the changing loads. When not working, the engine does not want to idle properly, and makes you think the engine is going to die at stop lites. Hope this helps.

I have a couple of problems with my geo... I have a '95, 3cyl... for one, it burns up oil like you wouldn't believe. I always have to add more oil to it way before its time to change it. Also, it grinds when going into gears sometimes, especially 1st. I've been told maybe its linkeage because I'm not losing power, which I guess would mean the clutch was going out (which would suck big time). Other than that, its a great car... except for not having a/c... good car, good car.

i have 93 geo metro that runs well but when the gas tank is less than half full the engine cuts out then fires back up then shuts off,but will start back up. fill the tank up and it will run fine.replaced the tank but no change.any ideas?

I'm not that familiar with the innards, but does the Metro have a lift pump in the gas tank? If so, when you replaced the tank, did you replace the lift pump? If you did (or if Metros don't have lift pumps) can you check the fuel pump in the engine bay?

Below link is a Metro owners forum, post problem and many knowledgeable people will help.
http://autos.groups.yahoo.com/group/thegeometroclub/

1993 3 cylinder GEO Metro 48000.6 miles
I have a problem all seems to be working fuel,fire.compression,charging system,good take off power for 3 cylinder as long as you hold the gas down not all the way it will pas 30 and 40 with no problem.
It is longing up and down between 30 & 40 MPH. on the road when I slow down to the 30 or 40 MPH.up to 30 and on to 40 after that its ok, and when you crank it with out giving it a little gas the engine runes ruff as hell.
From an idle to about the RPM that would be 30 to 40 MPH it lounges up and down but go up with the RPM and its OK.
Need help

Hum the last post I can find for the originator of this thread http://members.gardenweb.com/members/drumminfool,
is May 2005...wouldn't it be nice if he told us what he found out? Maybe he discovered he didn't understand how to work the mpg arithmetic and was too embarrassed to confess.

Well, looks like we have a new question: a lightly used '93 Metro, only 48K miles, that's a little over 3K per year, doing arithmetic in the "head"...and embarrassed if incorrect :>), this must be near a low mileage record. Could that have anything to do with the, what I understand to be, a bad hesitation problem?

Maybe all it needs is some "gumout" in the gas and/or directly into the carburetor.

WOW thats so funny i have the same problem as the guy who started this article... Was getting about 40 mpg now im getting 20 to 23 mpg and i have 153k miles on it but feel no difference in the car. I have 3cyl. 1 liter, 2 door convertable geo metro... I wish i knew what he found out though.......

I have a 93 geo metro that cuts out momentarily after topping a hill or coasting or easing off of the gas pedal, never during acceleration or climbing a hill. Any ideas?

check the compression middle cylinder may have burnt valves mine did

I have a 1996 geo metro with 3 cylinder and 5 speed. Does a 1996 have elecrical rest button or cutoff for the fuel pump and where is located?

i have a 95 metro .. runs great but idles rough and when i try to start it is take a lot of cranks be4 it will start and have to give it bout half throttle !!!!!!!anyideas ????