this is pathetic, and its really burning me. I'm getting about 6-8 city mpg and about 15-18 mpg highway. I'm 17, and this is absolutely destroying my wallet. How can i get my gas mileage up to like 15 city, 22 highway? please, i need this.

 

1- Oxygen sensor.

2- tune up, incl plugs, wires, distrib/timing, oil change, fuel filter, air filter, that haven't been changed very recently.

3- (least likely) Vehicle speed sensor. when this was disconnected on my first car, it took 1/2 a tank to drive it home 26 miles.

but what engine/trans do you have, and have you modified anything? if you spend most of your time idling in stop & go, gas mileage is less relevant than gas mileage compared to average speed. if you spend 1/2 hour to go 3 miles in a city, don't expect to get 15mpg.

 

Check vaccum leaks too, oil pressure, fuel pressure, etc. While youre at it get your tires aligned too.

 

compression check also

and if you can a leak down test

 

i have a 305ci with auto tranny, no idea what specifically the tranmission.

 

What year car? what type of induction does it have? Is it TPI TBI CCC or did someonw throw a double pumper or something similar on there?

 

its a 1986 4bbl

 

Since no one else has said this.. drive with a light foot.

 

That's fairly average mileage with a stock carbed engine. If you want better gas mileage, might want to go to fuel injection, but that's a tad pricey.

 

No it's not!

A stock 305 4 bbl should get 17 to 18 mpg in town and at least 25 on the highway.

 

You're saying a stock carb will get the same mileage as a stock fuel injected car?

 

If set up right, yes.
I had a '79 T/A that got 26 MPG on the highway at 80 mph, using a 403, rochester 4bbl and TH 350 trans with 2:71 rear.
Cheyenne, Wyoming to Omaha, Nebraska on 1 tank of gas (502 miles)

Keep your foot out of it and don't drive like a wild man.

 

I agree, keep your foot out of it, and get the motor in tune. Q-jets can get some incredible mileage because of their tiny primaries. Having a carb is no excuse for poor gas mileage. Go to the carb board and figure out how to tune your carburetor, then set teh timing, do a compression test and swap the plugs and wires. Basically a simple tune up.
matt

 

But then that's not stock anymore.



I agree there, driving habits make a huge difference in mileage.

I'm not trying to insult anyone here, I'm just saying carbs and fuelies weren't rated the same mpg. A well-tuned carb can see some great mileage.l

 

Sure it is. Just because you rebuild the carb and adjust it for peak performance doesn't mean it isn't stock. On my T/A the only mods done were headers, dual exhaust and a velocity stack under the shaker scoop. Never once tore into the engine, all stock.

 

dam<X>n i wish i could do that with my 79 bird. it has a castrated 301 and only gets 22 hwy 10-14 in town (depending which town, the bigger the city the worse the mileage) and that's from the factory? whats the deal?

 

Perhaps we have different views on the meaning of stock, then.

Rebuild? Fine, that's pretty much stock since it doesn't really change the specs of the carb.

Adjusted? That's no longer stock, it takes the car out of the manufacturer's specs. If you mean rejetting, then that's certainly not stock as it changes the air/fuel ratio. Even if you didn't rejet the carb, and only tweaked what you had, that wouldn't be a stock engine. If you flash the eprom and put in your own tables and what-not, or if you change the spark curve of the distributor, you may have mostly stock parts but it isn't a stock setup.

Now that being said... a properly tuned and adjusted carb, stock or not, can give good gas mileage. And since we've forgotten about the original topic of this post...

Rebuild the carb, see the carb board for more info there.. Do a complete tune-up, as posted before.. plugs, wires, cap/rotor, fuel filter, air filter, etc.

 

Ummm when you rebuild a carb you MUST readjust it, and adjusting a carb for optimal performance and or economy is putting it back to mfg's specs. No rejetting or changing of the metering rods, just a basic and complete rebuild.
The engine is still stock, it is just performing as intended.

 

My 85 trans am stock with lg4 got 17 mpg in town and around 25-27 on the highway.

Ben

 

QJets are the all time champion carbs for mileage, no question there.

I KNOW that an LG4 gets 18 mpg around town--it was my own car!!!

 

My 86' IROC LG4 5-speed got 17 city and 24 highway, and it was bone stock. That was also doing 75-80 most of the time in the highway, so 25 is possible if you drive nice. I would say do a full tune-up, carb rebuild, and make sure your catalytic converter isn't plugged.

If you follow the trend of the fuel injected cars, they generally don't get any better mileage than the previous years, or even the carburated versions, but they produce more power. When GM comes out with a more efficient way to burn fuel, they would rather make the car faster than increase the mileage(unless they have to due to CAFE laws).

 

Back to the origional topic.... After a tune up you can try running a larger tire... I put 275/60-15s on my car and noticed a big increase in mileage.