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Discussion Starter · #1 ·
Hi everyone!

This is my very first car so I have a lot of funny questions.
After 7 months of driving I've decided to check a fuel economy. It was disappointing. Only 18.2-18.5 city and 24-25 highway. I've expected around 24/32, to be honest.

As far as I understand after reading this forum is that there are a few common reasons for bad mpg:
- air filter;
- fuel filter;
- ignition coil / spark plugs;
- tires alingment / balance;

I'm interested in fixing it one-by-one to detect the actual reason. Also I'd like to try to fix it with my own hands (as far as I can, though).
So tonight's question is:

- what is the easiest thing to start from the list above? :)

Thanks
 

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Not serious, right?


Start with telling how you figured the MPG., and be honest about driving habits as well.

Some figure using the gas gauge, some think "normal" shifting means revving it up in each gear - we can't guess unless you tell.

Then the first check is tire pressure/looking at tires for signs of NOT rolling smooth/straight, and jacking to spin all tires looking for drag.

Get it checked for pending codes, like any for a misfire. After that you can start with the "tune-up" type maint.
 

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Air filter in the engine bay...replace it with motorcraft or go with K&N for 40 more dollars, but lasts lifetime. Plus better performance.

Its probably easy in the correct way you listed them.

Driving habits can be the biggest downfall. How often you are on highway going !!! miles an hour.
 

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i get about 22city 30 highway... thats with a helluvalot less stop and go traffic than LA

your numbers seem ok...
 

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Discussion Starter · #7 ·
thanks
I've got an automatic gearbox.
although I try to drive as smooth as possible, I'm not skilled driver and that can affect mpg for sure. but anyway it seems to me too low.
my bad, tires were a bit under inflated for a while [headbang]
I guess there is definitely a problem with my wheels — at 70 mph I can feel a steering wheel vibrates a bit.
 

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Vibration Happens to me too, so it was under inflated tires?



Tires that have more pressure transfer more vibrations than soft squishy ones. You can play with psi till you find a happy medium.
 

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Air filter (engine) and plugs and plug wires would be the easiest to replace. YouTube has lots of hot to videos that are helpful if you've never done it before.

Best I've ever got out of me and my wifes cars (she has a ZX3) is 22 city. The only things I HAVEN'T replaced on the cars is the coil packs and fuel filters. Love the Zetec engine, but it's not going to be breaking any MPG records! :-D
 

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Had similar trouble with my Duratec engine Focus. Along with the things already posted figure out how to spray a can of intake tract cleaner into the engine intake close to but upstream from the throttle blade. All the surfaces inside the intake tract get dirty and need cleaned. Ask for Intake Tract Cleaner at the auto parts store/dept. Do not use carburetor cleaner! It helped my car. Do this before installing new spark plugs, if possible. Otherwise don't sweat it. Many people have different opinions about this, but changing the engine air filter element and fuel filter every 25,000 miles or so is a good idea. Try to accelerate from the stop lights a little slower that the cars next to you for a while. I know it's not natural. Check your mileage carefully after that. miles driven(use your odometer)/gallons of gas used-fill the tank every time
Hope this helps
Oh yeah, when it comes time for tires don't get wide ones. Get stock size tires. Wide tires have more rolling friction -resistance- and are heavier than stock size tires. More rolling friction means less gas mileage.
 

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im gonna wait to see how his properly inflated tires do before suggesting you spend money.
 

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Discussion Starter · #13 ·
nboyles85737, most likely tires were under inflated

Robby04ZX5, please do not destroy my world [:D]

Highball116, [pray]

dooor, thanks for the advice :) I'll try that thing with intake cleaner.

but nboyles85737 is right — I'll see first if mpg changed when tires are inflated properly.
 

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changing oil every 3000 miles? i notice a bit more oomf when i change my oil. next would be plugs and a filter....
 

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What nboyles said. Be aware that what you need goes on sale frequently and coupons can help reduce costs. Yeah, I do stuff like that.
 

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Discussion Starter · #18 ·
have changed an air filter yesterday and got a trip to San Diego and back.
it resulted in 31 mpg (previous highway mpg value was 25)

I'm kinda satisfied but can't believe only a new air filter affected that much
 

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have changed an air filter yesterday and got a trip to San Diego and back.
it resulted in 31 mpg (previous highway mpg value was 25)

I'm kinda satisfied but can't believe only a new air filter affected that much
All depends on how dirty the air filter is, as to how much the MPG is affected, but 6 mpg seems like a pretty high jump just for an air filter.

It wouldnt be a bad idea to keep up with the other maintenance as everyone else has mentioned.

One thing to remember to, is that MPG is usually lower in the winter time due to the winter blend fuel. I personally drop about 5-8 mpg in the winter.
 
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