98civdx

It's a 98 DX, auto, fully stock Y7 about 206k on it. I only run shell gas, mostly 87, but run premuim every now and then.

I have been getting bad gas milage lately, by bad I mean 16-18 mpg.
I was getting 22-25 in the last few months, this is mixed city/highway, but mostly city.

Plugs are 2 weeks old, and a light grey color. I did pull them and check after I noticed the crappy gas milage. Wires are year old as well.
I have no clue when the cap,rotor were changed last. I am assuming they are 13 years old with 200k on them.
I will be doing OEM cap,rotor, fuel filter this weekend, in hopes that fixes the issue.

But I was still wondering if I should run some sort of cleaner through it, my dad says yes, but I have got no clue what to use.

I was thinking gum-out, but my friend said seafoam. What do you guys think I should use, or what have you used with good results?

93egSLEEPER

I always use Stabil fuel treatment or Chevron Injector cleaner. Lucas makes a fuel system cleaner as well that works well.

As far as the bad gas milealge goes are you throwing and CELs? Also a plugged up cat or O2 sensor going out can make a big difference as well.

SeanK325

I've used Lucas and Chevron Fuel System cleaner. The Chevron is the best stuff I've ever used. It took me two bottles to finally see results, but I got an extra 10-15 miles back on my tank. Our daily driver is a 2005 Saturn Ion and we were getting about 22 mpg in pure city driving. After the bottle, it went to 23-24 mpg. Drives a little better, too. Lucas sucks, from my experience.

JDyzzle

seafoam! all day lol

glockoma818

I would have to agree with the chevron brand. And Lucas does not work no matter how many bottles you use.

98civdx

Thanks guys.

There is no CEL. The primary o2 was replaced about 3 years ago, and it is a NGK. As far as the seconday, I am sure it is the same the car came with.

Is there any way to check if the cat or o2 is clugged?

I'll take a look at the chevron stuff.

cheggie

I have never known fuel injection cleaner to actually fix anything. It's ok for preventative maintenance, but its very unlikely to fix an existing problem. How are you calculating your mileage - by filling the tank completely and dividing trip odometer mileage by gallons used?
I would also not forget that bad alignment, dragging brakes, and low tire pressure can cause poor mileage.

98civdx

178 miles on a 10 gallon tank=17.8mpg.

Alignment, brakes, and tire pressure have not been touched. I was getting 22-25 on the same setup I am getting 17 on.

I really hope I don't need a cat, or o2. I already need a T-belt and water pump.

limperatlinks

TECHRON ALL DAY, THE BEST YOU CAN BUY, IF YOU HAVE A CHEVRON GAS STATION, START GOING THERE EVERYTIME YOU FILL UP

98civdx

Techron, it is. Thanks guys.

cheggie

The catalytic converter and 02 sensor would likely show a cel if they were bad.

The Civic's hold more than 10 gallons, but you can usually add about 10 gallons when it's on the 1/8 full mark. Did you add exactly 10 gallons?

I ask again because it's important. The only way to calculate mileage properly is to fill the car until the gas pump cuts off, reset the trip odometer, drive it until nearly empty, then refill once more until the gas pump cuts off. Only then will you have enough numbers to divide out the mileage. It's also more accurate if you record several fillups this way. I just want you to be sure you've got a problem before doing a lot of work to fix it.

Also, just because everything was good before, doesn't mean it's good now. If the obvious stuff is ok, you need to break out the tools and look at the brakes, check tire pressures, and see if the tires are wearing funny.

Remember, mileage is a sensitive number - everything's got to work together before you get a really good number back.

That being said, I have experienced better mileage out of some of the name brand fuels, like Shell, Chevron w/Techron, and BP. There are some differences in the quality of fuels out there.

Libertariat

I've used Seafoam before and never really noticed a difference. Maybe I'll have to try some of these other brands.

I'm tired of getting 32mpg. Something is wrong. My first civic, 97 hatch got 40mpg every fillup.

It also had a y7 transmission though. The Ex is a lot more fun

98civdx

I usaly get 9-10 gallons before the pump stops.

This last time, I got exactly 10 gallons out of it. I drove 178 miles on that 10 gallons.
I did 178/10 and got the 17.8.

I check the numbers every now and then, and have never ever gotten anything less the 20. And that is different, becuase I wasn't drving noramaly.

I never expect my numbers to be exactly the same as the last time, but when I see a 5-10mpg difference I get a little worried.
My driving habits aren't always the exactly the same, sometimes I am nicier to it than others. But this a 5-10 drop I feel is a little xtream when I was driving like a old lady.

I have also noticed different MPG numbers with different gas. This is why I normally stick to shell, as I have seen the best MPG #'s, and the most consitsent numbers.

The only thing suspesnion wise that changed was I lubed my poly sway bar bushings. The last time it got aligned (few months ago) all tires were set to 32psi. They're 15's with 195-55 tires, so I do expect to see a drop from them, but not this much. The last time I checked my the #'s I did have the same wheels.

98civdx

What!? Your complianing and you get 32mpg?

I always here that, my friend gets 40-45 (all highway) and he's bitching.
I need to hury up and convert this thing to 5spd.

On a side note
I talked to my brother last night, and told him I got 16mpg. He proceded to call my an *** hole and said he gets around 8-9 with his truck. (08 F450, Dullay) HAHAHA

Due to a train derailment my cap and rotor are sitting in portand. 2-3 hours from me. It says it will still be here today, but I have given up all hope of it making it. UPS can't tell me if it got ****ed in the accident or it is ok.

Linked

my last fillup i was able to stuff 12.4 gallons in my 94 ex. the pump didnt stop until 12.4 so i'm guessing the pump didnt read the gas level correctly, and i heard before that if a person that previously used the pump overfills their car, it will throw the pump off for the next person who fills up the their tank on that same pump so,idk

but i average around 390-400 miles before my tank starts to run dry (while 350 of those miles are on the interstate going about 80mph)

ill try some of that chevron stuff too

mavvrik

If your running a stock motor dont ever use high octane gasoline. Just use regular grade. High octane actually hurts your car over time--shortens the overall life span

98civdx

Huh, I have never gotten that much in mine. I would likely stop the pump before it got that high to began with.

I picked up 2 bottles this afternoon. Buy one get one free at autozone.
I put a little over half the bottle in my car (just over half a tank) So well see how what it does. I'll run both bottles if need be.



I have heard this before, but have never ever seen solid proof.

Please explain how it shortens the life span? I am really interested in this.

ecko_3420

iTrader: (1)

Bg bk44 has been good to me..this is what they use at dealerships for the fuel injection service..

98civdx

I saw that stuff, but was really unsure how it would do.

I am hoping this chevron stuff works.

Linked

well since my gas tank is 11.9 gal, i assumed the other half gallon is probably in the spout, i wasnt watching it while filing up this time, but thats the most i've ever put in the tank. ( i know i was getting pretty empty too since you have to prime the fuel pump a few times before it actually gets gas

98civdx

I try to never let me car get that low.

Linked

being a college student, thats actualy a pipe dream for me (keeping the tank above half)

98civdx

I know exactly how you feel, I am between jobs at the moment too. So all of the litltle issues my car is starting to have is coming out of my savings, which is almost done
I guess I better start looking lol

Cap and rotor, fuel came in yesterday. So, Ill be doing that today, and hoping that makes a difference.

Linked

doing my cap and rotor seemed to help my idle smooth out, my cap had corrosion at all of the points inside, and my rotor had a burnt tip.

98civdx

Im guessing mine will be the same if not worse. I am fairly sure it is the orginal.

Just shows how good honda stuff is. Show me a autozone cap and rotor that will last 200k lol