TTORA Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
46 Posts
Discussion Starter #1
So roughly a week ago my CEL came on and it gave me the following code:

- P0031 (Oxygen (A/F) Sensor Heater Control Circuit Low(Bank 1 Sensor 1))

I did not run any tests and the truck is at ~150k so I went ahead and ordered a new O2 sensor.

While waiting on the senor to arrive I have had no choice but to drive my Tacoma to and from work since it is my DD.

To my surprise I have averaged substantially better gas mileage since the CEL has came on? I average ~240 miles to a tank (2003 3.4L 4DR PRERUNNER) and below is a picture from this morning of where my tank sits now.



Driving habits haven't really changed - Any thoughts?
 

·
Registered
Joined
·
46 Posts
Discussion Starter #3
Average before CEL ~16.3MPG - Currently do not know what it is now since I have not gone through 1 tank... but at the current rate it looks like I will land at around 18+

I also havent noticed any difference in driving or engine performance.
 

·
Registered
Joined
·
105 Posts
Lots of things will go into effecting your gas mileage:

Air density (elevation), temperature, humidty, load (skinny pedal), tire pressure, tire type, spark plugs...etc.

As said above, I also notice a major difference in my mileage between the winter and summer. Sometimes as much as 4 mpg which may not sound like much but from 16 to 20 mpg thats a 25% increase.

Bottom line, I would continue with your planned maintenance and cross your fingers the fuel pump gods are on your side.
 

·
Registered
Joined
·
422 Posts
Lots of things will go into effecting your gas mileage:

Air density (elevation), temperature, humidty, load (skinny pedal), tire pressure, tire type, spark plugs...etc.

As said above, I also notice a major difference in my mileage between the winter and summer. Sometimes as much as 4 mpg which may not sound like much but from 16 to 20 mpg thats a 25% increase.

Bottom line, I would continue with your planned maintenance and cross your fingers the fuel pump gods are on your side.
That's exactly what i see.
 

·
Administrator
Joined
·
18,233 Posts
If you can truly attribute the increase in MPG to the CEL light, then that means your O2 sensor or another sensor is/was not functioning properly and giving the ECU bad readings. Most likely scenario is the O2 sensor was telling the engine to run too rich, causing you to burn excess fuel. When the CEL kicked in, the ECU used some default settings which trimmed down the fuel and in turn bumped up your MPG a little.

Replacing the O2 sensor and clearing the CEL should maintain the higher MPGs.
 

·
Registered
Joined
·
1,031 Posts
i think you got better mpg's because of weight reduction, apparently your windshield fluid is empty:D.

I'm rolling a 01 V6 ext cab A/T, daily driver and was averaging about 18mpg with stock gearing and 305/75R16's. im getting about 19 now with stock 5-star wheels and 285/75R16's on there. I have a CEL, i've had it for a month now since i bought the truck (possible bad ECM) but i put new O2's in there, new wires/plugs, new fuel filter and aired up my tires and clean my MAF. I'll be able to let you know soon if my MPG's increase after i fix the CEL that's throwing a code related to a bad A/F O2 sensor.
 
1 - 12 of 12 Posts
Top