Extremely low MPG warming up

jabulon · Mar 8, 2011

Hi!
I have owned a 2007 zx3 2.0 for about 5 months now. It is my first car so I don't really have anything to compare it to, but, I have noticed that now during the winter, the car is wasting fuel in an astonishing rate if I drive it without a few minutes of warm up. My warm up is : turning the engine on, waiting until the rpm's reach below 2k, and start driving very slowly, keeping below 2k rpm. If I don't follow this procedure, I can see my fuel level drop very fast! something like a 1/10 of a tank in 10 minutes.
So,
Is there anyone else having this 'issue' ?
If not, could it be related to the fuel filter? The car has 47k miles and I don't think it was ever changed.
Thanks in advance!
[ffrocks]

iroc34 · Mar 8, 2011

Probably not. It is usually the winter formulation of fuel. Seems the mileage always goes down with this fuel. And the fuel filter should be changed every 25k iirc. I always let my car warm up for 4 or 5 minutes when its really cold..

Mike_Mac · Mar 8, 2011

when the engine is warming up it will run rich till its warmed up. when i had my 04 on the road my wideband would read 10-11 afr will the temp guage was about 1/4. after that cruise bounced around 14.5-15 afr cruising/light to moderate throttle. so that in combination with winter gas, and ethanol in the gas my gas mileage is the complete shit till its warmer out.

jabulon · Mar 8, 2011

thanks!
So I guess I'll need the fuel filter anyway. Is it something that can be done at home? (I do have a hydraulic floor jack) Or do I have to take it to a shop?

Mike_Mac · Mar 8, 2011

not sure how different it is from doing a 00-04 but i have done a few on my cars and it only takes 15 ish min. most of the time you will be fiddling with clips to get them off, small hands are a huge plus lol.

iroc34 · Mar 8, 2011

You can do it at home. Up on jack stands, dont ever get under a car on the jack. A good maintainence manual is a good idea. You should pull the fuel pump fuse and let the car idle until it runs out of gas. This takes all the pressure out of the system Then remove and replace the FF.

jabulon · Mar 8, 2011

thanks guys!

@iroc34 : this sound kinda dangerous :O ! will it be able to re-suck the fuel back without help?
And before I begin, can anyone point me in the direction of which filter I'll need to buy ?
thank you!

iroc34 · Mar 9, 2011

Any time you get under an object that can fall on you and kill you its dangerous
Make sure you take every precaution that is available to you. And once you have the new filter installed, Put the fuel pump fuse back in, turn the key to on, not start. Do that 2 or 3 times to re pressurize the system, at that point, check your work for leaks, if non are found start the car. Also one last point, install the new filter in the same direction as the one that you removed. There should be an arrow on the filter. Pointing from tank, to engine...

whynotthinkwhynot · Mar 8, 2011

Yes and familiarize yourself with jacking points on that vehicle. Places that were acceptable jack points on other vehicles- like the control arm- are not acceptable on this vehicle. I actually prefer to find jack stands and jacks with slots for the pinch weld which is where most small cars are jacked from. Some might have pads in front of the back wheels and behind the front wheels for lifts.

deezx5 · Mar 9, 2011

I think the 2007 fuel filter replacement is the same as the 00-04. Here are some directions I used on my 2002. You can also back up on ramps to do the fuel filter if you don't want to mess with jacks, whatever you do be safe and wear eye protection.

The part number is Motorcraft FG986B and you can get at most parts stores, Or Fram G8018 can be found at Walmart. Cost is $10-15

Extremely low MPG warming up

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