Bad gas mileage... looking for a fix?

[edwx]

Good point, plus you can save a couple of hundred bucks if you do the tune up yourself. It doesn't consist of much these days......plugs, air filter, fuel filter, and maybe an oil change, and a bunch of Techron. That's about it, unless I missed something.

 

[nramacciato]

I started doing a bit of highway driving and got a reading of 9.3 MPG in the vehicle itself. On Fuelly, I got a reading of 9.7.. so highway driving does help, but I've seen people doing much better. I'll continue and see if it ever raises again.

Before I started the highway driving, I got a bottle of Heet gas line antifreeze, apparently it removes water from the tank itself. Basically I had less than half a tank left of gas, poured it in, and drove on the highway until it got even lower (I didn't run it dry, nor did the low fuel indicator pop up). Fueled up right after that. A mechanic recommended that I do it, and he also told me about fuel injector cleaner.

Is it worth it to try that out as well, or would I be wasting my time?

 

[dantheman68]

I'm going to go out on a limb here & say this might have something to do with the poor MPG.

Zero to anything driving, especially for a younger driver, is the worst for any vehicle. A lot of stop & go, like somebody who doesn't use a highway might experience, is going to result in terrible MPG.

I thought the exact same thing when I read "Junior License". Don't take offense, most of were exactly the same, hence speaking from experience.

9 mpg is pretty bad, but it might be within the tolerances. The EPA 13 mpg is an "average" city rating, meaning some will get worse, some will get better. Does your gas station use ethanol?... That can equate to a measurable decrease in fuel economy, a car getting 13 mpg on 100% dino would not surprise me to get 9-10 on 90/10 gas/ethanol.

The #1 thing that will change gas mileage other than fixing a mechanical failure is driving habits.
- Use your brakes the least amount possible, not saying to run red lights, but look ahead and coast as much to a stop as you can.
- Use small changes to throttle to come to speed (people will say drive like there's an egg under your foot.


As far as mechanics, a basic tuneup will help your car run right and get the best MPGs. Plugs/wires/air filter will help if you're running aged mechanicals.

Also, most people will change O2's only when the light is on... The light will tell you when they fail for sure, but how do we know that the O2s aren't reporting "acceptable" inaccurate readings... I've had good according to the PCM O2's replaced and seen a significant MPG change for the better, leading me to believe that the O2's were not working to their potential, but well enough that the PCM wasn't any wiser... I think a pair of motorcraft upstreams are <$100... do both at the same time, and leave the downstream alone. The only thing the downstream does is test catalyst efficiency, so that one should ONLY be replaced when the CEL IS on.