Ok I have a 94 civic dx that's been converted to an Si mainly with the d16z6.

Ive been consistently getting 31-32 mpg on a front end that has been lowered 2in. and not aligned by its previous owner and i just got it aligned today and I am gonna be getting some new Falken ziex 912. I'm wondering if with the car being aligned and getting new tires if that will give me even better fuel economy? Maybe near 40 mpg (that would be awesome ).

I used to have a Dodge Neon and the best economy i could get was a little over 20mpg so i love getting over 30 mpg mixed hwy/city driving

 

Just by alignment?

Nope.

Now, properly inflated tires, a more conservative driving style, and maybe some general maintenance items might boost you 3-4, but that's it.

 

The thing is that the alignment was pretty bad (it was chewing through the tires that i had on it and i was thinking that that is causing greater rolling resistance

 

It's possible. I'm actually curious to see numbers now.

 

I will let you know after a few fill ups Ive done a pretty good job of keeping track of my mileage.

Its really nice having to only have to fill up my tank about every 2 weeks. I'm really starting to love Honda.

One more thing to credit Honda engineering is, i recently got a power steering pump out of a car at the junkyard with the front end smashed, brought it home cleaned it up put it in and i didn't have any noisy pumps no belt squealing no nothin.

 

well i come from driving a 15 mpr truck, the civic i purchased a few weeks ago was at 26 mpg but its now at 32 mpg after a new fuel filter, plugs, wires, pcv valve iol and filter. it still has P0420 code but need to test cat and O2 sensor before buying one or the other, so after I fix that and start shifting earlier from now on I hope to be at 35 mpg or better.

 

I just got my new tires installed General tire altimax Hp from tire rack. I have no more steering pull and no vibrations and now im wondering how my mileage will be.

Come on big numbers.

 

Alignment can have a big impact on fuel economy, I am a journeyman heavy equipment tech with 15 years automotive experience and to say that alignment does not affect fuel economy is not true in the least. Anything that affects the tire to pavement contact will affect fuel mileage, that is why underinflated and overinfalted tires make a difference. How much it impacts fuel economy is more dependant on vehicle but it does definately make a difference. It can also prematurely wear steering parts if its not corrected.

 

Bought a 2000 Civic LX sedan a couple of weeks ago. The car has 144k miles and seems to run well despite the 0420 code. On the highway doing 75-80 I estimate I am getting 32-33mpg. I was hoping to do better than that. I thought perhaps a tune up - new plugs, etc may increase that some. Is that being unrealistic or am I getting about expected.
Regardless it is much better than the Suburban I was driving.

 

I have a '91 Civic Dx using regular 87 octane, I get about 27-29mpg, so I'm a bit "J" of your 32-33mpg.

I tried using the "pulse and glide" technique to see if it works. I heard of people using this in hybrid cars, where they accelerate (pulse) up to 75mph, then release the gas pedal (glide) down to 55mph, giving them an average speed of 65mph. So I don't clog this post anymore than I have to... please see the link for more information.
http://www.metrompg.com/posts/pulse-and-glide.htm

Anyway... I dedicated 2 whole tanks to this driving style, recorded the data using a simple (miles driven) / (fuel used) = (mpg) formula. Then dedicated 2 tanks to not using pulse and glide. I was pretty shocked to find that I got about 2-4mpg gain which almost gave me 1 extra trip to work.

Since I used a modified version of this technique, where I merely depress the clutch to "glide" while in gear--instead of taking it out of gear or worse... turning the car off (yikes)... My only worry was that I didn't know if this would put significant wear on my clutch, so I stopped using it. I didn't think the money I saved on gas would even come close to a new clutch if I prematurely damaged it; however, I also didn't know how much sooner it would cause me to have to change it either. Furthermore... This technique can potentially be dangerous as it can delay or impair your ability to react to an emergency.

Anyone hear or used this technique before? I've read about some pretty unbelievable results out there with Prius's and Metro's.