[krazymatt]

I got this 07 Civic Auto EX Coupe back in April used with 8k miles. The first tank with me it averaged 33mpg. Then after I changed the oil and started doing my normal 30 mile one way commute with the car to work I averaged 34mpg 90% of the time. I've gotten up to 36, but always ended up at about 34 mpg on my commute to work which is 70% highway, 30% city/rural.

My probleem is, for that last 3-4 tanks, I've averaged like 29-31mpg. The car has 17k miles now. I even took the car in for an alignment and that didn't change a thing even though it was slightly off. There's no engine lights, but I have noticed a slight decline in power it seems. Any ideas why I would lose 5mpg overnight like that?

My next plan is to visit the dealer, but I already know that song and dance. Usually if there is no engine lights on or such on the dash, then it means they are going to tell me "sorry sir, we couldn't find anything wrong."--and I waste my precious time yet again on the dealer service department. In my experience with dealer service departments is; if it doesn't knock them on the head they won't find it. In other words the car has to have a light on, or plain old not start and run. If I had a dollar for every service advisor that told me they couldn't "reproduce the problem," I'd a paid off a car by now.

Any ideas and input would be greatly appreciated. Thanks in advance...

I love the car otherwise, but for 29-30mpg, I could have a 4cyl Accord and have more room.

[Tragedy]

I have a faulty fuel sender in my car that causes my gas guage to read inaccurate fuel levels. It is in the 1/4 tank margin.

If this is not your issue, try checking the o2 sensors and other little stuff first before having the dealership mess with it. Good luck.

[krazymatt]

My gas guage is fine. It's just when I hand calculate my gas mileage is where the problem is. I'm lucky to get 300 miles per tank as where I've gotten upwards of 400 in the past.

I'm wondering about the fuel filter. Would that cause poor mileage?

Also I usually tank up at Sams Club. Is Sams Club gas bad quality? Could it be the gas causing poor mileage? I was thinking of trying Chevron or something for a couple tanks to see.

Wouldn't o2 sensors and such cause a light in the dash to come on?

[Tragedy]

lol I was half awake when I posted. Just noticed you drive a 2007, sorry dude.

[HonCiv02]

other things i would consider are air conditioning usage and any changes in how you drive it (hard accelerating, hard stopping, driving above 70-75 mph on the highway). there are a lot of things that contribute to fuel economy that could be affecting it. just my .02 and some things to consider.

[krazymatt]

That's the thing, is that the car sees the same drive and driver; day in and day out. Not much has changed as far as A/C use either. Matter of fact I was still getting around 35 in early August-Late July, definitely A/C weather.
The Air Filter is a brand new K & N.

The next thing is the fuel filter. Does anyone know where the fuel filter is on this car? Thanks...

[rocksinger]

Try this put an egg between the accelerator pedal and your foot. It worked for me. Cheap gas like ARCO here in the west has lots of alcohol in it that seems to evaporate long before your engine gets to use it. Hence poor gas milage.

[Tiznonay]

hmmm, Ive got an 06 LX, and I've noticed that I get a couple more MPG with Chevron than I do with any other gas. If thats not the problem, than its probably the way you're driving. Last summer I was getting like 25 mpg around town with the AC on constantly. This summer im getting over 30, all cuz I stopped driving fast. Its amazing what our engines are capable of when you drive em like a grandma.

[plastics]

It may be that the stations around your area has started to pump "winter gas".

In the winter, they use a different gas formulation to control smog, but it also results in lower mileage.

Plastics

[krazymatt]

Thanks for the input guys. I'm currently running a tank of Shell and I plan to try Chevron next and see if it makes any difference. I loved my car initially, but man little things like the gas mileage change has me ticked off right now. Another off topic thing which is annoying is the wiper replacement. I can't find the wipers anywhere and I understand they are super difficult to replace according to other people on this forum. I'm thinking of trading already, but for what? Is there a better car for commuting than a Honda?

[ericsd]

I use to get like 34 mpg then it fell below 30 mpg, I really think it's the gas quality. Sam's gas is lower quality

Honda civic 06 ex auto

[krazymatt]

Well I haven't yet calculated the MPG with the Shell gas, but so far I'm at about 310 miles and I still have quarter tank. Before I was looking for a gas station at 300 miles so I do see a big difference with the Shell. I'll see if Chevron does the same. That Sam's Club Gas is full of water or alcohol--who knows maybe even piss!

[gearbox]

i got 10mpg more mileage just by accelerating slowly and keeping rpm below 3k. this is easy at sea level but hard in hilly areas.

[gn3ric]

Hello everyone,

I am also getting weird gas mileage with my car. It's a 2007 Sedan Auto Ex and ever since i got the car gas mileage sucked. Even after break in period, i average like 29-30 and on a whole tank i only get like 310-320 and the light comes on. Oh and i do not drive like a speed racer mostly calm although, in my area there are many freeways and locals. Most of my traveling happens on both local and freeway. I'm at 17k miles now and recently a week and half ago i did an oil change. Ever since i got the car my brother told me to use 5w-30 and now I decided to go with what was recommended by the cap and dealer 5w-20. Been running with the new oil for about 2 weeks and a half and still came out to be the same crap. Any body out there with 07 Sedan auto ex been getting something like this? Or is it that LX gets better gas mileage because of no moon roof, rims, etc. One last thing, I found this site where a guy has an LX Auto and has 45k miles on it and he gets really good mpg on it. He posted some pics of his gas mileage and oil change. check it out
http://www.honda-tech.com/zerothread/2368382

someone explain ?

[gearbox]

alot of people arent too happy with the newer civics mileage. not sure if its only some cars, but ive heard that even some newer hybrids were only getting 26 mpg. but most of it comes down to where you live and how you drive. that link you posted is not that impressive either, thats what most civics from 0 yrs ago were still getting. full synthetic isnt the best idea either. i used to get 32-34 mpg in illinois (sea level, flat roads) using regular dino oil in my 02 civic with mods.