My truck now has 68,000 miles on it and I have been debating replacing the O2 sensors. My mileage has declined just a bit and I was wondering if anyone has any thoughts on replacing the O2 sensors? I am not very familiar with them and need advice to mileage and or time interval they should be replaced. Thanks in advance.

 

I have had them replaced in my 'company car' F150 every 50k, same with the plugs.

My Expy hasn't got but 32k on her yet

 

If my truck had 65k+ mles on it, I would consider it to be a prime candidate for new O2 sensors. Assuming your truck has the four O2 sensor configuration, you want to change the upstream sensors. those are the two that are closest to the engine. The downstream sensors are after the cats, and really are just there to tell the pcm that cats are installed. Bosch makes a good O2 sensor. In fact, that may well be what is on your truck at present.

Those O2 sensors' performance can degrade over time without being so far out of spec to trigger the check engine light.

Sensor change is rather easy on a cold engine: just disconnect battery cable and then swap them out.

 

Im getting close to 90,000 miles and haven't had any reason to replace the O2 sensors or the plugs... I have as much power, as good of gas milage and as smooth of an idle as I did when it was brand new...

 

my 99 has 22k miles, no problems witht the sensors yet.

 

STX/98 makes a strong point for the arguement of "if it ain't broke, don't fix it"!!!!

 

Bosch recommends changing the O2 sensor every 50-000 to 100,000 miles.

 

Hi All,

For best performance & mileage, we recommend changing the O2 sensors at 30K miles intervals. Now that will of course come as a shock to some, but in our years of experience this is a normal maintenance item just like a fuel filter or anything else, and it has a useful service life limit. In performance applications (and even in normal daily drivers for those of us fanatical about best performance & mileage), that is about 30K miles.

Most people don't do anything about O2 sensors until they actually fail, but best performance & mileage will be had with a 30K mile service interval. There is a simple test to check the response rate of the O2 sensors, and it's easy to pass that with an old O2 sensor but still not be up to snuff. That is just one of many reasons why we stick to set mileage intervals for replacement.

In "performance" applications, we're a bit more demanding than say, "normal" daily driver usage, so a 50K mile interval could be used and not give up too much. We don't do that even on any of our mildest vehicles or our custoemrs who have significant modifications, we stick to a 30K mile change interval.

All of that being said, we only replace the *upstream* O2 sensors only at these intervals (not all 4 O2's, just 2 of them), which is the O2 sensor closest to the engine on each side of the motor, the O2 sensor *before* the catalyic converters, as it's only the upstream O2's that the PCM needs for A/F ratio feedback/control during closed loop operation.

The 2 downstream O2 sensors (the unit after the cats on each side of the motor) we leave in place for at least 50K miles or until they fail. The downstream O2 sensors are there strictly to monitor catalytic converter function, and do not affect tuning. So it's only the 2 upstream units we recommend treating as a routine maintenance interval item.

 

BOSCH Oxygen Sensor

O.E. DESIGN - w/CONNECTOR - BEFORE CATALYST - MFR SUGGESTS TO CHECK/REPLACE AT 100,000 MILES

 

Thanks Mike, I was thinking of doing the change simply because of the mileage on the truck. I have installed a Superchips and I seen a mpg increase but I don't think it was much more then when I switched to premium fuel before the chip. Then it was a wash, reduce mileage with regular fuel or increased mileage running premium? Basically, it worked out to be about the same in $. However, the O2 sensor has been one of those things I've been wondering about. I am pretty **** about the maintanence on this truck. Oil and filter change every 3,000, fuel filter every 15,000, and transmission fluid and filter every 30,000. I guess I will pick up the new O2 sensors tomorrow and install them on my next days off from work. Thanks everyone for your input. I also have to change rear end grease as well.

 

Someone tell me if my logic is inaccurate here... In order to 'break even' with 92 octane gas (as opposed to 87 octane gas) I'm figuring you would have to get right at 60 more miles per tank with 92 octane gas than 87 (which I belive comes out to around 2.5 more miles per gallon.) If you have a 25 gallon tank, with an average cost of .20 cents more per gallon for the 92 octane gas, you'd be paying approximately $5 more each time you fill up your tank. For a guy useing 87 octane gas, that $5 would buy right at 4 gallons of gas which would take you probably 60 miles on average (at 15mpg). I get between 325 and 350 miles per tank on average. Surely I wouldn't be up over 400 miles per tank strictly by useing a higher octane gas would I? (I've actually used 92 before, and did not notice atleast any difference in mpg.) So how is it so many people claim to be breaking even useing the higher octane gas?

 

I routinily get over 400 miles per tank, on Reg Unl no less, but then I have a 30 gallon tank too . . .

Don't get a SuperChip, or any other 'performance' mod in an attempt to gain fuel mileage. As you noted the cost out weigh the fuel economy benifits, by far, and your comparision didn't even take into consideration the $cost of the chip

Get 'performance' mods to gain performance. It will take drastic changes in driving habits to gain substaintial fuel economy increases. (smaller truck maybe?) For example a 10% increase, which is pretty substaintial percentage wise, only eqautes to about 1.5 mpg and certainly not worth hundreds of dollars. BUT, an extra 20-25 HP, now thats a differant arguement altogether!

 

STX, I can't argue with your figures but I can tell you when I checked the mileage of reg vs prem it was only about .10-.12 per gallon difference. Also the Superchip was not an attempt to increase mileage but since that was one of the claimed benefits I was wondering why I I hadn't seen any gains to speak of. I really was wondering if replacing the o2 sensors would help bring the mileage back up a bit.

 

I WOULD LOVE TO HAVE MORE INFO ON THE SENSORS, AS I AM FROM SOUTH AFRICA THE SENSORS ARE NOT WELL DISTRIBUTED YET, AND THEY GUYS WHO DO SUPPLY THEM CHARGE $550 EACH!
WHAT IS THE PART CODE, AND WHAT SHOULD WE BE PAYING BEFORE SHIPMENT COSTS IN DOLLARS!!
WE GET RIPPED OFF BIG TIME WITH US AUTOPARTS!!
THANX!!!

 

After I installed my chip, I have not seen any lower than a 2mpg gain. The normal is about 2.5 and a high of 3. Everytime I fill up, I am actually getting back $.40 more than I did with 87. The ebst thing is, that I got this gain, and I am driving the truck harder now. Go Figure.