i usually get around 280-310 for a full tank and lately ive been getting around 240-270.

i have aem v2 and greddy evo cat back & the car has 90+k miles

how can u tell if an o2 sensor is going bad cuz my friend said it could be that

 

well if the o2 sensor was bad i would believe you would throw a cell... they aren't to expensive though and with that many miles you should change it anyways... your cat could also have become clogged, either that, or your driving conditions have changed ie, more uphill, more city driving, more WOT driving, etc.

 

my driving conditions havent really changed besides that ill drive my gf's freind with us on the weekend sometimes so thats extra weight.

 

i been getting bad mileage too. i also have intake and exhaust

 

could it be from the loss of back pressure when i got the exhuast?

 

are you burning oil ? because i think when you burn oil your mpg gets worse

 

not burning oil, but ive gotten like 210 miles and im right above the e line. im u usuall at like 270 when im there

 

Most likely it's the o2 sensor. Mine went bad and it really hurt the gas mileage. I have a cx with the one wire and it didn't throw a code. It was always reading lean so it kept adding more fuel all the time. I ran for a week with it disconnected while I was waiting for a replacement and I got better mileage with it unplugged. You can check it with a multimeter or a ociliscope. It should be constantly changing voltage up and down. If you get no voltage or it's stuck at a certain level than it's bad. It should chang between .1 to .95ish volts min to max.

 

the gas meter isnt always accurate, esp the lower half, what you should do is when u get gas, write down the miles and gallons, then divide, thats more accurate, do it for a while and check it out. maybe u need to check basic stuff like air filter, plugs, etc.. good luck

 

My gas mileage just started feeling like it sucks too....BUT, YOU KNOW WHAT....I JUST THINK ITS THE ****** GAS PRICES HURTING US ALL....

THANK GOD WE GOT 4 CYL HONDAS AND NOT 8 CYL TRUCKS!!!

 

Less backpressure (from your new exhaust) will help mileage, not hurt it. The problem could be many things.


1. Are you using the same station and pump to fill up everytime?
2. Has the weather changed drastically?
3. How is the air pressure in your tires?
4. How recent is your tune up?

Etc.

 

1. yup same gas station and same exact pump every time
2. its cali, the weather always changes drastically, it was pouring yesterday and its hot today.
3. i checked them last night and all 4 were at 30 psi. max is 51 on ziex's
4. ive never done one . i know i definately need new plugs cuz i checked up a month ago and needed some and oil is getting there so that will need to be changed too.

what EXACTLY consists of a tune up?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93ejay1 &raquo;</TD></TR><TR><TD CLASS="quote">what EXACTLY consists of a tune up?</TD></TR></TABLE>

Depends....they can be as basic as just changing your spark plugs to as much asil, oil filter, air filter, fuel filter, plugs, wires, dist cap, dist rotor, and a couple other things.

I suggest you change your oil (seafoam it, search 'seafoam' you'll get a million hits) Clean your air filter (if its dirty, change you plugs, wires(both NGK), dist cap and rotor all with OEM parts. That should give you a smoother running engine and better gas milage.

 

My guess is a tuneup will return most of your lost MPG.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DBLAZE &raquo;</TD></TR><TR><TD CLASS="quote">My gas mileage just started feeling like it sucks too....BUT, YOU KNOW WHAT....I JUST THINK ITS THE ****** GAS PRICES HURTING US ALL....

THANK GOD WE GOT 4 CYL HONDAS AND NOT 8 CYL TRUCKS!!!</TD></TR></TABLE>

LOL I agree.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93ejay1 &raquo;</TD></TR><TR><TD CLASS="quote">my driving conditions havent really changed besides that ill drive my gf's freind with us on the weekend sometimes so thats extra weight.</TD></TR></TABLE>

is she 800 LBS?

Yea def. give it a good tune up... I think all this was probably b/c of your plugs b/c you said that you needed new ones. But it that doesn't fix it, then get rid of your g/f friend man, she is a heavy isn't she?? J/K!!

 

haha shes kinda big but not disgustingly big, just say shes a littler bgger but shes cool. ill just give my car a tune up i guess. what do u guys suggest i replace for a car with 92k miles?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93ejay1 &raquo;</TD></TR><TR><TD CLASS="quote">haha shes kinda big but not disgustingly big, just say shes a littler bgger but shes cool. ill just give my car a tune up i guess. what do u guys suggest i replace for a car with 92k miles?</TD></TR></TABLE>

Refer to the list above.

At least:

Plugs
Wires
Cap
Rotor
Fuel Filter

 

yea i was just kiddin gabout her being big...

don't forget to change oil and filter! also check to see if your antifreeze is ok and tranny oil.