97EX

So i have a stock 97 EX. I usually get inbetween 470 and 540 k's to a tank depending on how i drive.(usually fill up a little above the empty line). Anyways, a couple weeks ago i started to get about 380 or so to a full tank. I changed the fuel filter, air filter, spark plugs, ran sum sunoco gold/octane booster and fuel injector cleaner. And I'm still only approx. low 400's.

Any ideas as to why?

thnx

D.T.P

Check your distributor cap/rotor, that will/may help a bit, also look into the primary o2 sensor.

Bradsma

I know it sounds simple, have you been warming your car up in the morning or before you go for a drive. When you idle you get zero miles to the gallon.

black_and_orange

well i was getting the same maybe even less, so i did a engine oil flush and my gas mileage went back to normal. i'm averaging 425-450km's to a tank at speeds 120-130kph (no i was not speeding, i was on my way to and from florida)

jdm_77

maybe you should try a compression text to see if everythings normal because i heard if one cylinder is lower then the others that could cause poor gas mileage.

clkio

the fact is its the winter, the car uses a little more gas in the winter. I got a 97 b16a si, and I use to get 480k out of a 40L tank. Now I don't even get 420.

jamie1985

colder outside temperatures = richer air/fuel mixture = higher fuel consumption

97EX

that would make sense. i don't warm the car up before i drive. i probably could use a good flush. u think my 02 could be bad even if my ce light isnt on?

chris_v2

Could be some-what lazy. If it's the main issue for real low fuel mileage, the light will be on (assuming it's obd2). OBD1 vehicles won't turn the light on.

JDMej1

probably has some to do with the weather, but check out your dizzy and such to be safe

97EX

cool. thanx alot guys

3rdgen3

Wow you guys really get that bad mileage out of your D16y7 and y8's?

I would definitely look closely at your O2 sensors, also do you have any exhaust leaks?

My old D16y7 5-speed in my Coupe averaged about 500-550km's in the winter and 550-600 in the summer with mixed city/highway driving.

My y8 5-speed I have now gets almost identical mileage as my y7 did, except a bit worse cuz i step on the throttle more frequently cuz I like to hear the noise/vtec

A plugged cat will really kill your mileage also....and if I were you id check to see if your car has now developed a crack on the exhaust manifold where the primary O2 sensor screws in. If there is a crack there, it will definitely screw with your mileage and not necessarily through a catalyst efficiency code just yet..

97EX

i dont think i have an exhaust leak. it sounds just fine. i think i need to have the o2's checked. so, chrisv2, u were saying that an 02 may be faulty even if there isnt a ce light?

97EX

how much is it for an oil flush?

3rdgen3

You could very well have a crack in your manifold under the hood...or like i said earlier a plugged cat...

And yes a falty/lazy O2 wont necessarily through a CEL right away

97EX

doesnt a plugged cat smell like eggs? i gotta take it o sumone to check out

_andross_

It's winter...same **** is happening to me

I used to get around 550 km in the summer....now I'd be lucky to get 400 km

then again I remote start my car sometimes so that's no surprise lol

poopoohead

petrol companies change their mix of fuels 8 diff times a year, adding additives n such to compensate for temp and climate changes. that being said, the winter gas has diff chems compared to gas in summer, wihch results in a crappier fuel consumption

9HatchSi3

check tire preassure while you're at it