First time try to change o2 and spark plugs after 200K. Does any one know the o2 part numbers for 2001 astro. I know that the are two part numbers. But which one I have to have two o2 and just one o2?
Any help is appreciated.

 

You have 4 02 sensors. On each side of the motor you have a downstream and an upstream sensor. Both upstream sensors have the same number and both downstream sensors have the same part number. Log into a site like Rock Auto and put in your information and it will show you the correct sensor for your 01 Astro. Same with the spark plugs. Don't buy the real cheap ones.