O2 sensor

Hey,
I have a 92 silverado with the 4.3 L V6. I am getting pretty poor gas milage and had read on another thread that I should go ahead and replace the o2 sensor and that could help a lot. Do you guys know where these are located and how many I have on my truck. Also, are there any considerations I should keep in mind as I change these?
Thanks,
Jimmy Dager

Well, I replaced the it on my '92 5.0 v-8. There was just one on the exhaust manifold on the driver's side. Should be only one on yours too i beleive. They can be a bi$#h to get off. I recommend getting a O2 sensor socket, breaker bar, and a nice peice of pipe to go over the bar for more leverage. They rust on and with the constant expanding and contracting will not want to move at all. Soak it in WD-40 for a hour or so. then try to get it off. Should come off then, but some have had to heat it up to get it off. When you put the new on on, make sure it has anti-seize compund on the threads. also, disconnect the batt. so the computer will re-learn how to run the truck with the new sensor. Good luck.

Easiest way to get it out is to do it hot,right after you have driven it. Just make sure you have welding gloves on to prevent burns. I have never had a problem getting them out this way.

I just changed mine as well (94 5.7 that just turned 100,000) Before I changed the sensor I was at about 12.5 mpg and after the first tank of gas, I was at 14.3 mpg. Not a huge gain but with the price of gas these days it will pay for itself in no time.

Joe, I did not disconnect the battery. Would that possibly increase my mpg more?

Joe, I did not disconnect the battery. Would that possibly increase my mpg more?

No probably not. The computer will figure it out eventually. It just "learns" faster when the batt. is disconnected. It takes in as much info as possible on the first start and until the engine goes to warm idle. No big deal.

is it easier to replace the dang thing when the engine is hot? Manifold will expand with heat and the sensor will come off easier? Mine may be original!!! (ouch) and is pretty rusty. I am going to spray with some PB Breaker to hopefully loosen it up. Any other suggestions?