14mpg :-(
 

So my car started getting complete crap for mileage, and the check engine light came on. Pulled an o2 sensor code, so I replaced both oxygen sensors ($98/ea) and I'm still getting 14mpg, and developed an EGR code :( I know we have sh*t gas out here (damn ethanol) but any common problem areas I could check as to what would be killing my economy? I'm currently driving my truck cuz it gets roughly the same mileage and diesel is currently cheaper than premium...

Re: 14mpg :-(
 

How old is your CTS? Mine wasn't giving a code, but was running rough on start-up. Changed the CTS and jumped 5 mpg.

Get the CTS right from Subaru!!!

Re: 14mpg :-(
 

What is a CTS and why did you change it if you didn't have a code for it?

Re: 14mpg :-(
 

Coolant temperature Sender??

Re: 14mpg :-(
 

Indeed. Even before it throws a code, it can be in bad enough shape to make starting the engine a challenge.

Re: 14mpg :-(
 

Changed your air filter recently? How about spark plugs? Using the A/C a lot? Any one of these could contribute to your poor gas mileage.

(Point of Reference: I usually get 18-19, but can get down to 16 with a lot of A/C use and no highway miles)

Re: 14mpg :-(
 

I have stated many times that the 02 sensor code is a catch all code. Trevor isn't here now to declare war on me so I feel relatively safe repeating it.

I feel for everyone on the "damn ethanol". When the "gestapo" started making the oil companies include 10%, our gas mileage dropped at least 10%

Translation... it was at the very least of no value to us.

Keith:cool:

Re: 14mpg :-(
 

How is the 02 sensor code a "catch-all"?

Re: 14mpg :-(
 

The code comes up frequently when nothing is actually wrong with the 02 sensors. This is pretty easy to prove when one or both 02 sensors are replaced after getting a code and the problem continues to exist and the same 02 cod is generated.

The computer wrongly gives an 02 code because it senses a problem in the system that would be the result of a bad sensor but is not an actual 02 problem... a seeping head gasket for one can cause this to occur.

There are other things also and that is why I call it the "catch all" thingie. (probably not the technical name):lol:

Keith:cool:

Re: 14mpg :-(
 

Ethanol in gas is a multi-purpose villain. I've run nothing in my cars but the cheapest no-name E10 swill and both get high teens around town and high twenties on the highway. The silver recently cracked 30 mpg for the first time. With AC.

dcb

Re: 14mpg :-(
 

I got a new read on my MPG today and it was 22. That's about 50/50 city/hwy and some use of A/C. I have never gotten a read on pure highway.

Re: 14mpg :-(
 

Twenty two is a good number. I started logging mileage closely when fuel prices spiked here in the wake of hurricane Katrina, and my average in both cars is 21-and-change. Most of my driving is pure grocery gettin'. Road trips come in consistently at 27-29 mpg.

Getting back to the topic, I'd disconnect the battery overnight, drive for awhile, record the mileage scrupulously, and see how it looks.

Once I got a brief flicker of a CEL with an accompanying oxygen sensor code, did nothing, and the car probably runs better now than it did back then.

dcb

Re: 14mpg :-(
 

+1 on this point. Have you done any underhood work recently? A disconnected intake tube hose causing vacuum leak?

What brand of O2 sensor did you buy?

Re: 14mpg :-(
 

Talking of 02 sensors issues, I've got a strange one. Got 02 and knock sensor codes back from a CEL. Replaced them both all was good for 12 days then the 02 code comes back. Take it back to the dealer, new plugs (had 100km) and gaskets for the exhaust to insure no leaks. 13 days later 02 code again. Back to the dealer, he wants me to buy a new MAF, even though there is nothing to indicate there is a problem with it. They will not consider that perhaps they got a defective 02 sensor. The car drives perfectly with the CEL on, idles perfectly, not a single issue except I'm sick of seeing the CEL on every two weeks....any ideas as to where to start looking or should I just make the order another 02 senor and see if it comes back on?

Re: 14mpg :-(
 

Did an 11k mile cross-country trip last year in the '92 and averaged an overall 28 mpg on regular unleaded. If you are getting 14 mpg something is definitely not right.:eek:

Good Luck &

Cheers!