Front O2 sensor isn't bad to replace. Just make sure you use an ACDelco replacement

 

Yes, this is the one you see if you look between the firewall and the engine. Mine came out very easily. I would spray it down with some type of penetrant just to be safe.

The other O2 sensor on these cars is where the U-bend is in the exhaust and is after the Cat. These are not as important as the pre-cat and just pretty much monitors what the cat is doing. I don't typically replaced these unless they set off a code for that particular one.

On all of my newer vehicles that have the four wire sensors I replace the pre-cat O2 sensor at around 100,000 miles. On my car with a one wire sensor, I replace every 30,000 miles.

Even though you won't see any regular recommendations from the factory on O2 sensor replacements as a maintainence item, there is a lot of info out there that regular replacements are beneficial.

If you ever have a scanner hooked up to the car and look at the pre-cat sensor values as the car is running and the sensors are switching at a slow rate, that is a pretty good indication that the sensor needs to be replaced even if the CEL is not on. Good luck.

Wayne

 

i would do a tune up as in change the plugs with new ones. it will help as well i have the 3.5 but i did mine at 60k and again at 100k just to get them out of the way and start fresh because i do a mix of driving city and high way. more highway and very few city driving. but i would do a tune up as well as every thing sugested because some thing is not right because getting that low milege is wiered.

 

So wait, around how many miles do you guys get out of a full tank????

 

I am averaging 28.1 over the last two tank fulls. I got 487 miles out of my last tank of gas.

Keep in mind, my Monte has the 3.5L and I do 90% hwy driving. If I really jump on mine a lot, and drive it over 80mph, it gets more like 25MPG. All city, dips me down to 21ish.

 

I can usually squeeze around 325 miles out of a tank before it needs filled. Honestly it could probably go to around 350 miles on a tank but I never let it dip that low since it can damage the fuel pump.

I average around 17-20 MPG depending on where I'm working, which route I take, and how hard I get on it from time to time.

 

ugh this is so emabarrasing for me i mainly get a meisly 250 tops smh....

 

I can usually get around 380-450 miles on my tank, depending on if I'm just driving back and forth in town or driving on the highway. I usually get on the gas quite a bit when im driving too

 

Ok so heres the deal my upstream o2 sensor just came in i ordered it from 1aauto.com, i got my seafoam and my chevron techron ready, but im thinking should i wait to fix my oil leak because i know you have to change the oil after using seafoam. So should i wait to fix the leak or just wait till i have a little bit of gas left to do the seafoam, chevron, and replace the sensor?

 

You can change your sensor while adding the seafoam in the gas tank.

Where is your oil leak coming from?

I would add the seafoam in the oil, run it for approx 200 miles, then change your spark plugs/oil and also fix your leak at the same time.