Ok my fiances car gets really crappy gas mileage like 85-100 miles per half tank. It has new wires, plugs, fuel filter. I searched and found that a bad 02 sensor could be the problem also...but the car doesn't get any codes. So how else can i check if the sensor is bad or not? Also how can I tell if the CAT is clogged or not?

Thanks.

 

i had a problem like this on my gsr, i would always let my car warm up before driving it. but one day i took off in a hurry and the cel light came on and when i restarted the car the cel light turned off. i used to get like 20mpg. it sucks ***.i then bought a new o2 from autozone and right away with the first tank of gas i noticed 28 city and 33highway.

sorry moral of this post is had i let the car warm up i wouldnt have seen that cel come on.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaless &raquo;</TD></TR><TR><TD CLASS="quote">Ok my fiances car gets really crappy gas mileage like 85-100 miles per half tank. It has new wires, plugs, fuel filter. I searched and found that a bad 02 sensor could be the problem also...but the car doesn't get any codes. So how else can i check if the sensor is bad or not? Also how can I tell if the CAT is clogged or not?

Thanks.</TD></TR></TABLE>

My car is doing the same thing. I'm almost positive it's the 02 sensor. They only have a rated life of around 60K; and they can be bad without throwing a code. What happens is their response time slows (up to 50%), and so you're not getting the optimum fuel ratio delivered when needed; but they're still working, so you don't get a code.

They can be tested, but sometimes it will show them as still being good, but they'll still have a slow response time when in use. If she has a lot of miles on the car, it could be time for a change.

On that note: Does anyone know where I can get OEM replacement 02 sensors without paying $200? I need to replace both, but haven't had the money, which is why I haven't done it yet. I've been told aftermarket and Bosch replacements from AZ or the parts stores don't work very well in a Honda (like most non-oem stuff)

 

Bad fuel mileage can be caused by a slew of things from excessive back pressure (clogged exhaust) or the fuel delivery circuit (almost every sensor imaginable).

It could be the O2 sensor going bad, but it can also be the:

timing
tps
coolant temperature sensor
fuel pressure
injector leak
act
knock sensor
map
dragging brakes
etc......

Sometimes, the sensors will become lazy, thus creative an overly rich mixture. It is best to not change the o2 right away and test the sensors one by one. Labor intensive though...

Or bring it for diagnostic at your local shop.

fs

 

Well the car is totally stock minus i made a Intake for it used pieces left over from my old Regular ION....before the AEM one was out i made my own CAI for it. The car has about 160k on her and time for another oil change....i have another Z6 header in my garage i will pull the 02 sensor off and put it on hers today that is if the sensor will come off at all I know there a pain in the ****.