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sarandil

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Discussion starter · #1 ·
hey all new to the forums first off id like to say hi. now on to my question i have a 2003 ford focus zx3 with 2.3L duratec i was getting 30 mpg now its down to 15mpg most of my driving is in town delivering pizza, i know this is rough on fuel mileage but that much of a drop? just looking for some ideas on where to start. there are no engine codes popping up or anything the car runs smooth no fuel smell, well it vibrates a lil bit if im at a stop light with the AC on but other than that its smooth, seems to have plenty of power. im just not sure where to start with it.
thanks for any advice i really do apperciate it
 
#2 ·
30 is too high for running around in town delivering Pizzas, 15 is too low unless you leave it running all the time.

If figured well from actual miles per gallon when filled up, start by checking for a dragging brake. Might not be obvious when it first starts. Feel for a wheel that's hotter than others, and/or jack up & spin them.
 
#3 ·
As someone is hinting at, I'll be more direct, your mileage change is too drastic to not have something NOTICEABLY wrong with the car, ergo, the readings are faulty.
 
#4 ·
Now way are you getting 30mpg delivering pizzas, unless its all freeway. Improve your mpg by making your motor more efficent by swapping out the plugs, fuel filter, cleaning the t/b to start. A bsd will help w/mpg & is a cheap mod, as is a steeda sri vs the oem filter. As well as your driving skills. Your vibration is more likey your psm needs to be changed out= Ford/Motorcraft only, not the place to go cheap,,,,,,,,,,
 
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Discussion starter · #5 ·
re

the 30 mpg was before delivering pizzas sorry i should have clarified, but the 15mpg is accurate reading now filled up drove 150 miles filled up /w 10.1 gal. i dont drive fast rpms never hit 3k.
 
#6 ·
Close to 30 is the best I ever got in an '04 2.3 5spd for mixed driving, so just hitting it is possible with a different mix.

On the other hand, seen as low as the 20-22 range with short trips & bad weather.

Don't know what king of driving is involved in the pizza deliveries, the shorter the trips & the more idling in traffic/at stops the worse it gets.

Automatic trans. if equipped will lower numbers in local driving.

Even before checking brakes as I suggested earlier, you can determine how well it coasts in neutral for a reference. Should glide right along without slowing very fast on the flat.
 
Discussion starter · #7 ·
it glides along just fine i do it all the time to try and increase the fuel mileage, it wants to glide for quite awhile also replaced the MAF recently if that makes a difference in narrowing down the diagnostic a bit
 
#8 ·
You didn't confirm transmission type or typical driving for the deliveries, but I'll add that keeping it in gear saves more fuel in most circumstances as the fuel cuts off completely after a short time with your foot off the accelerator.

When driving in neutral it takes fuel to keep the engine turning, more when A/C is on.

If you can let the relatively slow engine braking in top gear coast along as far as needed, then you're maximizing MPG without actually shutting it off.

Changing MAF should have a positive effect if the old wasn't working right, you haven't mentioned anything pointing to engine issues yet. Most issues would show a code, or pending one, even a free check for that might prove if there is an issue.

15 sounds ridiculously low, yet I remember one from CA with a MkIII that does even better for MPG getting results that low - drove less than a mile to work & back every day.
 
Discussion starter · #9 ·
auto trans, i dont take it out of gear to coast i leave it in gear, as far as typical driving i drive the speed limit i dont drive aggressive, i dont leave it idling. it's throwing no codes i will take the advice on replacing the psm due to the vibration, it just seems that i should still be doing better than 15mpg
 
#10 ·
Can't offer much more offhand, how many tanks have you checked to get an average? (individual can still have wide variation)

Missing the MkIII owner who delivered for a living, he might have had more input.

Where I grew up deliveries were mostly less than a mile, 2 at most one way. Here the joint I go to or order from has to go 1-5 at least one way for deliveries, and open roads for most of it. Neither had traffic tie ups, MPG quite different between them obviously.
 
#12 ·
I'd think you could get 20 something with that use, got a few things to think about now.

Did you reset the system when installing the MAF? (battery disconnect)

It might have had learning to do either way, but shouldn't kill mileage for a full tank.
 
#14 ·
Start with the basics check air pressure in tires, check air filter and make sure you can see sunlight through it and blow out with air, check oil and go synthetic and make sure your transmission fluid is okay and replace filter. I went from 26mpg to 32 on a Honda one time just doing those basic steps.
Look at your plugs make sure there not black and identify if there running lean or rich. There is a color chart to see if plugs are correct color.
 
#16 ·
TomPocono said:
What is a t/b?
What is a bsd?
What is a Steeda sri?
What is a psm?
Click to expand...
t/b = throttle body, the butterfly valve that controls air flow to the engine.

bsd = balance shaft delete. This only applies to the 2.3 duratec & the current ST models that use this twin shaft balancer assy. driven off the crank & located in the oil pan. Removal saves weight (~20 lb.) & lets the engine change RPM faster, little actual power/economy effect. Extra oil capacity when removed is a plus.

Steeda sri = Steeda brand short ram intake. A replacement intake before the t/b that includes an air filter. Not a great deal for the OP as it isn't CARB legal so the stock intake must be reinstalled for CARB testing. OP can look at the restriction gauge on the PZEV style intake to see if the air filter is still free flowing.

psm = passenger side mount. The engine mount on the right side of the car, a hydraulic damped unit that tends to transmit vibrations when worn so more direct contact is made from engine to frame. Ford is the only reliable supplier of these, aftermarket is often poor out of the box and short lived when the smoothest ride is desired.
 
Discussion starter · #17 ·
ok update after the MAF install i ran a tank of fuel through the car and went from 15 mpg to 17 i think ill try plugs and maybe o2 sensors next? any input will be apperciated =D oh and checked tire pressures thats all good
 
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sarandil
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