Amoeba

Well on my last couple tanks of gas I am getting terrible mileage, at the half way needle mark I was at about 102, and usually I get 125-130 at that point for all city driving. I have an 03 CL-S and I am trying to figure out why. I always put in 93 Premium.

I have Toyo T1S and have always kept the tire pressure at 38/37 and have no problems with mileage until now, I checked the pressure and it was fine.

Possible Reasons?

1) Would a dirty AEM filter cause it? I live in Florida where there is a lot of dust, dirt, and pollen and I havent cleaned it for 15,000 miles even though AEM says you dont have to until 25,000, because Florida conditions may be considered severe could my air filter be clogged up causing worse mileage?

2) Only other thing I could think of is a leak in my alphawerks headers? How would I be able to identify a leak? When I pop the hood there has always been engine noise and other noises that naturally I cant decipher anything.

So Im gonna clean the air filter, but if that doesnt work, then would my only other option to figure out the problem is to take it to acura to see if they can identify a header leak? Will they even look at it, since its aftermarket, although my dealership said they are mod friendly?

Shawn S

Why don’t you accurately check the mileage by filling up twice, writing down and tracking your miles?
The old “half tank 100 miles” method is highly inaccurate.

Amoeba

How inaccurate can it be when I get 125 at the middle mark for the past 2 years city driving? I drive hard all the time, so no I didnt get on it any harder this tank.

Even if my #2 question isnt the problem, how to identify a header leak would be good info for me, if anyone knows.

Allout

Header leak wouldn't cause this. You can feel around the flanges of the header for blowing or listen for a leak. Pressure in the Header is greater so any leak will blow out exhaust.

Bad O2 sensor?

ShawnS is right on filling up the tank to get an accurate MPG number so you know what you're dealing with. Gas guages can change over time.

Red-CL

A dirty air filter will kill you gas mileage.

Check that.

More than likely that's your problem.

turbobumblbee

i would most definatly clean that air filter and then check for a header leak as well, a small leak will not cause much of this problem but it should still be checked out as well..

also, just wondering why do you have the tire pressure set so high?? ive worked on and with cars for several years at shops before and at home.. we would always set the tire pressure to 32psi unless it was a heavy duty truck that required more..

Amoeba

I was told with the 215/50/17 toyo t1s that 38/37 is good from several memebers

anothercls

I recently filled up after a half a tank and got about 20mpg, which is terrible for me, but if I let it run down till the light comes on or close enough I get just about 30mpg. I'd suggest doing what Shawn said.

F900

I get close to 250miles on a half tank

Amoeba

Thanks, but im not asking what I should get, im just saying its lower than usual and asking what the culprit may be

andyjl

get a k&n air filter, you clean that every 60k miles, and get a fuel injection done for your car

MarbleGT

i think i found your culprit

RaviNJCLs

iTrader: (4)

I have had the same problem at times. But not consistantly. I would clean out your air filter, and injection system. Also, how many miles do you have on your car. I swapped out my spark plugs at about 45K and was surprised how fouled they were. I jumped up about 2 MPG after that.

I drive pretty hard a lot as well, and in the City. Lots of traffic, but I will still get about 125 to 130 to a half tank.

Also, I'm not sure about that tire pressure. I have never put more than 34 to 35 PSI's.

RaviNJCLs

iTrader: (4)

I'm jeolous. I don't even get that on the highway.

turbobumblbee

i would lower that a little bit.. i think that you have WAY too much air in your tires and if you lower the air pressure it will definatly help some and you will notice a change in the ride condition..

I would like to know how you pull that one off.. i ususally get about 150 at the half way mark and then i usually fill up around 320-330 to be in the safe site... you must do alot of highway driving or just take it real easy on the gas..

Shawn S

I still get a kick out of how many people calculate their mileage using the “half tank” method.
I wonder how many of you guys don’t know how easy it is to do it the right way.

MrDan

Wow - the MOST I've driven on a full tank was 377 miles (mixed highway/DC beltway traffic). And you're looking at 500? Do you always drive downhill on coast or something?

andre

i hardly reach 250 on a full tank. i'm noting these suggestions...

Amoeba

Ravin it looks like we have the same driving style,

to the person who said get a K&N filter, I have an AEM filter from my intake which is the same thing.

I am going to recharge my filter, lower the tire pressure a little, and lastly how do you clean your injector system? Do I need to bring it to Acura to do this, and how much is it to replace the spark plugs? I thought the plugs were supposed to last to 100k

Bobbydoedoe

i think u just head to pepboys and pick up a bottle of those injector cleaner

derelict

I hit the half tank mark today. Tripometer said 91 miles.

darrinb

reminds me, i think i am due for an intake cleaning i belive its been about 15k

F900

I've talked and posted about it before, I can get close to 500miles on a full talk. I believe i could hit just over 500miles 100% highway, no WOT, driving 70-80mph.

Right now i'm looking in upgrading the airfliter and Thermoblock package. If all goes well i should be well over 500miles which i will post the results.

BTW S Florida is Flat, we don't have any slopes lol


Here was my fuel review back in FEB

https://acurazine.com/forums/showthread.php?t=167685

mrblorry

F900 failed to mention that he just installed an eighty gallon gas tank.

fuzzy02CLS

iTrader: (2)

I get about 260 on a full tank just driving around town. I drive a bit hard though. Straight HW I get 380 or so if I keep my speed at 80.
Once you get past the 80 mark the CLS EATS gas. I was driving down to Boca from Clearwater. I did 100-110 for an hour down the turnpike at 2am last night. I blew through a half tank of gas.