Do i need new o2 sensors?

[phenomic]

I have a 97 z28 with 113k miles on it and it does run good but i am having gas mileage problems. Ive changed all the fluids/filters/plugs/wires/pcv valve/used seafoam/ and a few other things. I got some boltons and switched from a 160 stat to a 180 stat. I am getting about 13mpg driving suburban. I havent had a good chance to see how well it is on the highway. I don't lead foot it too much.

Well i was wondering if new o2s would make a difference or not? They may very well be the original ones in the car. Is there a good way to test the o2s without taking them out or is there any way to clean them?

 

[Alan]

Clean out the intake system.
Clean the MAF.
Use a good fuel injection cleaner.

 

[Matt_S]

O2 sensors can get lazy, not responding to changes in O2 levels quickly enough. You can check for this with a scanner. I'm not sure of the details, but I know it can be done. It's a pretty safe bet, though, that with the original sensors having 113k miles on them AND gas mileage problems, you need to replace the sensors.

 

[1sttruck]

I had a check engine light that would come and go and three different shops, two were Ford, couldn't fix it over almost a year period. I replaced one O2 sensor, thinking that I'd swap it with the remaining one before buying another if it didn't fix it, but it did fix the light. From what I've read you can try to clean them with a propane torch.

 

[BlazerLT]

13npg in the city is not bad in the winter time.

Colder temperatures really kill fuel economy.

 

[phenomic]

I cleaned the maf. intake. and fuel injector cleaner a few times. O2 sensors are the only thing i left because they are rather expensive. Ive been getting 13 in my are or less even in the summer. So im a little puzzled because a lot of lt1 guys get up to the 25s or more highway and about 15 city. It just bugs me because my tank is small and i have to fill up every few days which inconveniences me.

 

[andyd]

you can test O2 sensors with a voltmeter. they should swing rapidly between .2 and .9 v. if they dont fluctuate rapidly, or stick around midrange .4-.6 they are junk. BTW, , i had no luck reviving the O2 sensor with a torch. though the red hot tip did get to .9v

 

[davidfarming]

I have the same truck, 97, Z71. If you need O2 sensors, your check engine light will come on. I get about 14mpg driving around town and 19mpg on the highway.

 

[davidfarming]

Sorry, I mis-read your post. I thought you had a Z-71. But, I still believe that if your O2 sensors need changing, your OBDII computer will tell you.

 

[moribundman]

I had a smog check done with the old sensors still in the car last August, and I passed with flying colors. I recently replaced my over 133k mils old O2 sensors and gas mileage went considerably up. I would change old O2 sensors.

 

[Matt_S]

Actually, the computer won't always tell you. More often than not, by the time the computer picks up a problem, they're REALLY gone. The first symptom is poor gas mileage.

 

[daves66nova]

just go ahead and change them. im almost positive it will help.