Rep Power: 173

I've had my '03 EX for over 5 years now, and back home in AZ it used to get 410+ miles to the tank with pretty good consistency (I always reset my trip meter whenever I fill up). Last year I moved to WA and noticed that my mileage hovered to around the 350 area. Now, I am not a particularly aggressive driver so naturally I wasn't too happy with that!
I didn't know what was going on... my NGK Iridiums are only two years old, my tires are new and inflated to 35 psi, I switched to synthetic oil and a better filter last February (I'm embarrassed to say I had been using Fram High Mileage up until that point), and it's summer so I should be getting a little more out of my gas! I also used fuel additives every 2,000 miles or so. I also changed both 02 sensors a few tanks ago.
Well last month I forked over the money to buy a new WR Secret Weapon intake and a new set of grounding cables. While I was at it, I cleaned my throttle body out a bit. It wasn't too gross or anything though:



I didn't take the whole thing off but I sprayed the inside with cleaner and wiped it and the plate down to a shine. I did the idle relearn procedure and enjoyed my new mod! :-) That was three weeks ago. On my last tank, I still only got around 350 miles before I had to stop. Today however, I noticed this welcome sight:



I have to fill up tomorrow of course, but I'm happy with the improvement. I just ordered LC20 and FP Plus too, so I'm really hoping to get used to these numbers!

 
Rep Power: 193

I'm seeing similar things with my 01 Honda Civic. However, I haven't moved anywhere new. About 3-4 years ago, I was getting 44 mpg on the free way every time. Now, I'm getting 38 mpg. I'm still trying to figure it out. Although, interestingly, you and I have both changed to the same spark plugs, and in that time, I've noticed the drop in fuel efficiency. I don't see how it could be the spark plugs, but who knows? I've also done my AT trans fluid. Hmm, maybe it's time for a new car.

 
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I'm getting 36 in mixed (mostly freeway though) driving, and as I just bought this car I'll have to clean the throttle body and see I get an improvement. The type of fuel you use makes a big difference in economy. If the fuel you use has ethanol (like most of Washington's stations have) your economy will suffer because of it. I use a website puregas.org to find stations that sell ethanol free gas. It'll be worth it. I noticed a 1.5 mpg difference in my Yukon, which going from 15 to 16.5 was a big jump!

 
Rep Power: 173

Granted, that is a significant decrease but 38 mpg is better than my little car's ever done! Do you have an HX or something? Probably a dumb question but did you change the air filter, fuel filter, tires inflated correctly, brakes are not dragging, etc?
I'll make another post here once I run a couple of tanks with the Lubecontrol products too. I hope they help!

Wow, I never thought of that! Thanks for the info! Unfortunately, most of the stations listed for my area are marinas haha. It sucks that everyone still charges full dino prices for a diluted product. >:-( At least it's a little more eco-friendly...

 
Rep Power: 243

I have noticed that my 01 is very sensitive to highway vs city driving. I was living under 12 miles from my work in a more populated area and my mpg was close to 30 sometimes even under (with CAI). I have since moved 30 miles away from my work with more highway driving and I am averaging 35 (with CAI). The best I got was 39 on a non stop highway trip down the cost (it was stock then). I might change out my o2 sensor to see what happens to my mpg.

Boats are more sensitive to ethanol especially older ones so that is why marinas mostly have ethanol free fuel.

 
Rep Power: 173

I think I heard that most engines run most efficiently in the 50-60 MPH range or so. That, coupled with a lack of acceleration/deceleration would definitely have helped! Plus, I'll bet it was gorgeous :-) 35 MPG is still pretty good though!

Sounds like a good plan. At least the o2 sensors for our models are relatively cheap!

 
Rep Power: 313

Your mileage will vary GREATLY depending on what model you have. The EX civics get terrible gas mileage on the highway because they rev very high with their shorter gears. The other models besides the Si get much better mileage on the highway due to longer gears and lower RPMS. I had an EX and I drive tons of highway and averaged around 32MPG over like 100000 miles. Even when trying to hypermile it the transmission STILL limited me to around 36 MPG. The car was always tuned and taken care of. I think with the HX, LX, etc you can break 40 mpg but you have to be very very gentle on the throttle.

 
Rep Power: 0

I wondered at that...

Is it possible to do a trans swap or even a final gear change? I don't like having it scream down the highway at 70 and 3,400 rpm.

 
Rep Power: 173

Whew! I was wondering about that! My dad's automatic '05 EX 4-door revs lower at highway speed but he still seems to get about the same mileage as me. Maybe it's the higher weight or something.
Super noob question: When do you need to get your car tuned?

You can do a swap I guess (there are some threads around here discussing it) but think of it more as a performance feature than a problem. The EX is the second-best performing civic of a given year, next to the Si of course. The engine and transmission are just fine with sustaining higher RPMs like that.
There are some highways in AZ that have a 75 mph speed limit. At 80 MPH you should hear the car cruising... at 4,000RPM for two hours! It still gets about the same gas mileage though.

 
Rep Power: 313

The higher rpms don't cause damage.. per say to the engine. What they do however is cause the car to feel a little bit sportier and to accelerate a little bit faster. It depends to you what is more important. For me I should have gone with the non VTEC model because I drive.. a lot and the extra mileage would have been nice. The short gears do rock for bombing through the city though.

Tuning these cars is pretty easy. With no distributor or ignition wires to worry about you just simply need to follow the maintenance schedule in your manual. If anything gets too far out of whack it will usually throw a CEL.

You can swap to the other transmission they are DIRECT bolt on. Plus the non EX model transmissions are usually pretty cheap because most people don't understand the gearing ratios. As far as putting in a longer final gear I'm sure it's possible but I've never heard/seen it done and getting parts for it could be interesting.

Yes the EX also has the weight working against it because most people with an EX have a sunroof and all that fun stuff. The way you drive makes the biggest difference, if you are lighter on the pedal in your EX you can easily match his MPG. If he was the same on the pedal as you, you wouldn't stand a chance

 
Rep Power: 0

x2 on this, I love how i can essentially idle around in 5th gear in town... and still be able to go w/o downshifting, same works for the curvy roads i drive everyday. The EX ratio probably helps my MPG for my commute on a curvy 55 road

 
Rep Power: 313

55? No. It will help at about 40-45 MPG though. Anything above that and your better off to have any other model.

 
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I'm used to driving a big, heavy suv, so ANYTHING feels zippy to me, and the low gearing is nice for around town stuff, but I commute 23 miles on the interstate each way, at an average 70 mph, and I head home to my parents once or twice a year at 800 miles one way, so all-out fuel efficiency is what I'd rather have.

I didn't know squat about Honda's before I bought this one though, so I didn't know about the lower gearing in the EX, or I would have gone for the LX beside it. I just saw LX with an auto, EX with a manual, manual is always better on gas, plus I prefer manual, so manual it is.

I'll have to keep an eye out for a DX or LX manual trans for when it comes time to do the clutch...

 
Rep Power: 173

Whew, I HAVE been doing that stuff! For some reason I thought tuning involves dynos and computers haha. Thanks for the clarification!

Another area that the EX shines over the others is on two-lane highways. You know, when you have to pop it into 4th and fly past that van going 10MPH under the speed limit (who mysteriously speeds up as you pass him). Why would anyone settle for the other non-Si models? Well, anyone who views speed limits as LOWER limits. ;-) A SIXTH gear would have rocked our fuel economy though!

Can you honestly say that you made a mistake in getting a manual EX? It may not be the most fuel-efficient model by *CIVIC* standards, but it sure is a fun little car to drive, isn't it?!

 
Rep Power: 0

It's not bad, it's just not the "most ideal" for me and my use. Not a mistake in any way at all. And it is fun to drive, 1st and 2nd gear it pulls pretty hard, and since the previous owner did all the big money items (head gasket, timing belt, struts, etc) I can't really complain. I'm just picky and a hard to please modifierer/tinkerer. I'm always thinking, "Hmmm, that could be better..." or "If I change this, that will do better."

As for the manual v. auto thing, I'm the kind of person that, when the auto in my Yukon goes out, I might, I just might put an NV4500 manual in its place. So no, no mistake I guess, just a little bit of buyers remorse at all the coulda beens and what if's. Not that I'm unhappy with it at all, just thinking "I could have done better"

Ignore me, I'm tired and had a stressful day at work and yeah...

 
Rep Power: 173

Haha I wasn't for one second implying that you were grumpy! :-P You're definitely not the only one here who can see a better car hiding in the one they've got... we're all kind of like modern day Michaelangelos. The artist, not the turtle!

 
Rep Power: 0

It's a blessing, ...and a curse... :hugegrin:

 
Rep Power: 173

An expensive curse, that's for sure! I just got the Lubecontrol products last night after work, and I've driven 70 or so miles with them so far. I'll post some updates when I've gone through a couple of tanks to document any MPG improvements!

 
Rep Power: 366

have you guys gone through this?
https://www.civicforums.com/forums/1...e-up-mods.html

 
Rep Power: 366

ah, just as datapoint: my best mileage ever on the EX happened during my trip TN -> Quebec -> TN (lived in Quebec for a year and a half, so loaded the car with whatever i would need and drove there).
the way up did not get too good, sicne it was january, so winter blend.
but on the way back... may. warmer temps, no winter blend, car loaded so much that headlights were illuminating the skies.
from regular 28-32 MPG, it simply... shoot to 44 MPG.
what seem to have impacted:
1) up north, speed limits are 65 MPH, so went 70-72.
2) car loaded, so after it starts moving, nothing will stop it...
3) i used my stock 15" so it would be cheaper to buy snow tires, since it's mandatory in canada during the winter season. heavy as heel, so they start spinning, they don't wanna stop, again.
4) 20 hours highway driving, so any downhills, you just take the foot off the throttle and let it go (heavy as hell, so it will keep speed anyway) and let the fuel cut-off do it's magic.

my recommendation for non-maintenance items? learn to maintain the momentum. can the car turn the corner? then don't brake!

for maintenance, read the link above.

for an EX model upgrade, consider a crower stage 1 camshaft (drop-in) - it will give a little more ooomph to the lower-mid-range torque, so you don't need to stomp on the gas as much - that actually did improve my MPG (course, if you start stomping on teh gas more after cam, it could lower MPG, so driver consciousness matter)

 
Rep Power: 173

Yep, the o2 sensors and the TB so far, and I'll clean the EGR once I get that damn front bolt off. The PCV and the IACV soon and the evap canister next month when I change the oil.

I thought I heard that the more aggressive cams decrease engine life...

 
Rep Power: 313

Sandro. Winter tires are only admonitory in Quebec, I don't think any other provinces require it. I know Ontario doesn't anyway.

 
Rep Power: 366

the stage 1 is just making use of what the factory did not, so consider 25WHP with intake/header/exhaust, which is not much but if you consider the % over original HP, well, it's a ton
so these are pretty mild. Stage 2/3 requires a ton of changes, including ECU, but the s1 is drop-in. life might decrease if you keep revving too much (aka redline) all the time, as would with any engine/cam

thanks for the info, for me, since i was in QC there was no choice. I would have snow tires regardless of law, tho for obvious reasons

 
Rep Power: 313

We get just as much snow in Ontario yet they aren't mandatory

 
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I did some of those, just because I bought the car and I'm like that, but some are more trouble than I want to put up with for seemingly little effect. Things like the egr and evap filter (I did know about it) are those things that unless they go bad, I won't bother, same with the O2 sensor. I did clean the throttle body, with Seafoam and a brush, and since then, along with changing all the fluids, I'm seeing an improvement. This last tank I got 39.3 mpg, and that included three mountain passes... with a lot of engine braking downhill for many miles...

 
Rep Power: 189

I had an 01 LX and sold it and bought an 01 ex. (I didn't just buy it for the trim upgrade) and I've only noticed a 1-2 mpg difference in highway cruising at 75 between the two.

Blue-Something you said made me think that you got rid of the civic in the last week while I was away?

 
Rep Power: 173

Thanks for setting me straight!
I read your cam link! So you're still enjoying the new cam, huh? I found the cam online at Crower's site of course but I've yet to find a good step by step installation guide (with pictures a small child would understand)... I've been looking all over the forums for a while today. Everyone keeps saying it's easy and drop-in, but I'm nervous to open up my engine unless I have a REALLY good idea on what I'm doing. The only real guide I've found is on 7thgen and it's not quite what I'm looking for. http://www.7thgenhonda.com/forum/showthread.php?t=19492
So many mods, so little $$$ :-(

BTW I'm at 360ish miles and no fuel light so far :-)

 
Rep Power: 366

ah, that's because a lot of it is about the same as a timing belt change... of course, when you do timing belt or head gasket, you do much more work than swapping in a cam...
as example, here's blue em2's one, from his sig:
https://www.civicforums.com/forums/1...-belt-diy.html

 
Rep Power: 313

I really should finish that lol... too lazy.. Maybe when I remove the engine I'll take enough pictures to finish the DIY.

That's the proper way to do the job. You can cut that in half if you take shortcuts.

 
Rep Power: 0

Filled up yesterday, an unexpected expense took all my gas money with a week and a third of a tank until I got paid again... anyways, got 38 mpgs, and the tank took 12.4 gallons. I was getting a bit nervous when the low fuel light came on on Tuesday, but now I know that if I'm careful, I can get at least 475 miles out of the tank, good to know for SHTF situations...