Increasing the MPG's

[ItsBraulio]

I have a 1993 Corolla DX Wagon, with almost 294,400 miles on it. I've had the car for about 12 years. It had great mpg around 34 i think, but now its horrible. I made a trip this Saturday to Philadelphia. I filled up before i left, and went there and back and my gauge was on E. It was only 250 miles there and back! I've made regular oil changes since i got the car and always kept up with the maintenance. I know they have the seafoam and bg 44k stuff that supposively increases your mileage but is there a legit way to increase my mpg?!

[TheNightWolf]

Seafoam.

It does help a little.

[Dirty Dude]

Originally Posted by ItsBraulio

I filled up before i left, and went there and back and my gauge was on E. It was only 250 miles there and back!....

.... is there a legit way to increase my mpg?!

What was the actual fuel economy? You can't get a real number without knowing how many miles it went and how many gallons it used.

[bajaclam]

Put a code reader on it even without the check engine light on. It may just be an O2 sensor. Or the coolant temperature sensor.

Then there's the old routine:
Tire pressure maximum (35 psi)
Empty all the crap out of the car
Don't drive 80
Don't tie anything to the roof
Thinner oil (one reason for lower fuel economy is having to add heavier oil/additives to get rid of smoke)
New air filter, plugs, wires, cap, rotor (tune up)

And there's some out there who say to add a tiny bit of acetone to each tank of gas.

[TheNightWolf]

Originally Posted by bajaclam

Put a code reader on it even without the check engine light on. It may just be an O2 sensor. Or the coolant temperature sensor.

Then there's the old routine:
Tire pressure maximum (35 psi)
Empty all the crap out of the car
Don't drive 80
Don't tie anything to the roof
Thinner oil (one reason for lower fuel economy is having to add heavier oil/additives to get rid of smoke)
New air filter, plugs, wires, cap, rotor (tune up)

And there's some out there who say to add a tiny bit of acetone to each tank of gas.

Never heard of the acetone trick.


Clean injectors, and fuel system, that should bump the economy though.

I get 27mpg and mine has close to 260k miles.

[TheNightWolf]

I just read about puttting acetone in gas, and it makes sense.
The acetone decreases surface tension making it easier to vaporize and you aren't just blowing gas oujt of the motor.
Not sure how much acetone is the proper amount, and I honestly wouldn't do it.
But someone could try it.

[Dirty Dude]

The acetone "trick" is a complete scam. Real controlled testing(not unverifiable reports by anonymous people driving their cars around town) has shown it to offer no improvement at best and a decrease in burn efficiency at worst. Even Mythbusters verified this. I tried it myself in fairly consistent conditions and measured absolutely no change in economy outside of the standard deviation I was already getting. That means that adding acetone did nothing but raise the price of each fill up.

http://www.kettering.edu/visitors/st...p?storynum=406

http://mythbustersresults.com/episode53

http://www.snopes.com/autos/techno/acetone.asp

[QuietlyThinking]

My 93 DX Wagon gets around 27-29 mpg highway when I do the math

This says 30 highway and 23 city is normal for this car:
http://www.fueleconomy.gov/feg/noframes/10160.shtml

i'm not sure how you got 34. maybe the speed limit on the road you drive on was raised, I think the optimal speed for saving gas is something like 55 MPH

I keep my tires at 30 psi, which is what the sticker in the glove box says to keep it at, over inflating them wil improve mpg but the tires won't wear evenly, and the ride won't be as smooth.

Seafoam in the gas tank might help if your injectors are clogged.

250 miles should be about 8.6 Gallons(at least thats what I use when I drive that far), I think it is a 13 gallon tank, you probably did not run it bone dry right? With a few guesses you were probably getting somewhere around 20 MPG, but we can't be sure without knowing the amount of gas that you used. How much gas did you pay for at the pump, it says on your receipt.

[godanigo]

I get 33-34 on my 95 wagon, which hasn't had a tune-up or an oil change in who knows how long. Give it a tune-up. Unless you've been maintaining the car regularly that should make a difference.

Also, what I did....take off the roof rack if you have it on. You might see an increase.

In my 93 Prizm, under the right conditions I could get high 30's. Even got 42mpg once.

[PhatRoyale]

Best thing would be to get a tune up and keep up with maintenance. Sounds like you already did that.

I used to get awesome fuel mileage as well. Regularly 30+mpg in the city and high 30s on the highway. Some tanks even managed to squeak it a bit past 40mpg. That is until the government started mandating ethanol in gasoline. Then it took a nose dive and never recovered since.

I just accept it and adjust my driving habits accordingly.

[Piloter]

10% ethanol has resulted in about a 10% drop in mileage across the board for me. Best I can squeeze out, even at 55-65 for entire tanks of gas (ask me about my 320-mile commute every day last week!) and on flat stretches seems to be about 34.

Everything's already been mentioned so far except use of cruise control. If you've got it and if your terrain makes it a sensible choice, and if you do a fair bit of freeway driving...use it. It makes a surprising difference.

[cipher93]

Originally Posted by PhatRoyale

Best thing would be to get a tune up and keep up with maintenance. Sounds like you already did that.

I used to get awesome fuel mileage as well. Regularly 30+mpg in the city and high 30s on the highway. Some tanks even managed to squeak it a bit past 40mpg. That is until the government started mandating ethanol in gasoline. Then it took a nose dive and never recovered since.

I just accept it and adjust my driving habits accordingly.

+1. Used to get 30mpgs with the AC on and liberal use of the throttle. Now I probably accelerate half as hard as I used to and barely get 25-26mpg with my 3 speed. Using a bottle of Heet in a tank of fuel sometimes gets me an extra 1mpg, but I think it's just a fluke more than anything the additive does (I use it to remove moisture once a month).

In Pennsylvania ethanol free fuel is nonexistant too, so that is probably part of why you got such awful gas mileage. Also note your MPGs will nosedive when you switch between fuel types as the ECU adjusts, and it can take a couple tanks of the same fuel type (E10 vs 100% Gasoline) for it to rebound. Because of this I suggest trying to fuel up with the same brand of fuel when possible/economical (I'm lucky and where I also fill up is typically cheapist) and try to avoid using 10% ethanol fuels after a tank of normal gas and vice versa.

[Dirty Dude]

Originally Posted by QuietlyThinking

I keep my tires at 30 psi, which is what the sticker in the glove box says to keep it at, over inflating them wil improve mpg but the tires won't wear evenly, and the ride won't be as smooth.

Over inflating the tires will make them wear unevenly, not simply running them near the maximum pressure. I have always run my tires at the maximum rated pressure and the only ones with wear problems were on vehicles that needed alignment.

[Greasewrench]

i got 32mpg on my last tank, that's city and highway combined. thats pretty much what i get all the time, although if i use the A/C more, its less. and i keep my tires at about 34psi. recently i got a tire balance, rotation and wheel alignement. i did a full tune up, which helped alot. i bought NGK wires, new cap and rotor and bosch platinum +4 spark plugs. u can try and change the fuel filter and see if that helps.

[ItsBraulio]

Thanks for all the tips and info guys. I'm going to use seafoam in my fuel tank soon to see if that makes a difference. If that doesn't work, i might change the fuel filter.