O2 sensor condition

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Feb 17, 2007
Clermont, Florida
Last weekend I replaced my MAP sensor and did a tune up with new plugs, wires, cap and rotor. Today I replaced both upstream O2 sensors on my Dakota today. I ordered the OE parts from NGK.

I had no CEL on, I just did it as maintenance and to hopefully improve my MPG and if I get a little more power, that will be good too. I have 110,500 miles and was still running the original O2's. I did a test drive, truck seems to run a little stronger and had a smoother idle.

Question is, can you tell much about the engine's condtion by the condition of the sensor ends? They were both white to whitish-gray color. The holes in the business ends of the sensor were all clear and unobstructed. I know with spark plugs if they are white you are running too lean. Does it mean the same with an O2 or is it normal?

Thanks for any info you may have.
Your O2s are normal.
White on a plug does not mean a lean condition, especially with modern fuel - it means the heat range is correct or a maybe little warm.
To read the mixture, you read the bottom annular ring of color deep inside on the the insulator. Best checked with a full throttle when cut clean - no idling or part throttle.
Thanks for the replies and info. I thought everything was running OK too. Truck seems to have learned the new O2's now that I put about 100 miles on it this weekend and it really made a difference in power. It accelerates from a stop faster and pulls stronger. It's easier to pass other cars now and I really have to watch it to keep it under 70 MPH.

I'll know for sure about the MPG tomorrow when I buy gas, but it seems like the gas mileage is improving, just by using the gas gauge and guessing. It used to take almost 1/4 tank on the gauge to take the 50 mile trip to my girlfriend's house. Yesterday the same trip took a little more than half that. But I can't use the gauge to tell, so I have been writing down the mileage when I fill up and dividing the difference in miles from the last fill up by the amount of gallons purchased to figure the accurate MPG. With the new MAP sensor and tune up my MPG went from 16 to 17 in town to 19.23. That was on one tank, and I know it will vary from one week to another, but I am glad to see the improvement. If I can get another 2 to 3 MPG out of it with new O2's I will be glad.

The one other thing I may do is switch back to a 10W30 regular conventional Napa store brand 10W30 to see if it can help even more on my MPG. I have been using Napa HM 10W30, which I learned here that HM oils are thicker than the regular oil in the same grades. It will be time for my next OC in a few weeks anyway so that will be a good test. I'm just trying to get the most I can out of the gas I buy. It goes up more every day around here and I'm just waiting for it to hit $3.00 then $4.00 and beyond.

Thanks again.
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