Bank 2 sensor 1? drivers side upstream i think
 

does any 1 know which o2 sensor bank 2 sensor 1 is?
i think its drivers side upstream from cats, but not sure.
that's what coded at Knects today and i bought 1.
don't know if there is more probs but this is a start.
at $50 a shot i wanna get the right 1. i will get the others in time.

nobody? everyone must be having fun today, not just sittin' around.

Buuuuuuuuump.

Up stream sensor is closer to the exhaust manifold the down stream one is after the cat

+1 on stl's analysis . Just a friendly suggestion, diagnose then replace. What was the code that got thrown? FYI. I bought a SNG o2 recently. The price was right and so far so good. I got it online.

alright bank 2 is down stream bank one is up stream. and you only have one down stream so 1 is self explanatory

ps if you have a 4.0 or a 3.0 you will have 2 bank ones

you mean V motor.

I have the OEM replacement Ho2 sensors if anyone is looking for them.

thanks guys. i replaced and drove.
all is good.

Bank 2: driver side. sensor 1: upstream. easy hugh? lol! just didn't want to spend x-tra.
You guys are the BOMB! Excelent
.

thats good. just watch your check engine light. when one goes they all normally go

yea, it's probably a more serious prob than just my o2's. I have had trouble with cylinder missfires and other codes for a while and have just about run out of sensors to replace.

this thread got confusing for me so maybe i missed something . have you ever checked your fuel pressure and changed your fuel filter? what codes were you getting

have good gas psi, changed fuel filter 1.5 years ago. tps sensor, maf sensor, new ignition module, new plugs about every 2000 to 5000 miles because of cyl 6. all standard maint. also
have had codes for cyl 3 and 5 misfire, code on cyl 6 about 5 times,that plug is always going bad, and this new code for bank2 sensor 1: coded 3 times in 1 month.
I changed driver side upstream o2 and have drove it about 50 miles last night till the roads iced over and i barely made it home. will take it out today and play in the woods, all time watching for codes or lag in engine/shifting.
I may have forgot some of the troubleshooting i have done in past but that's about the just of it.

What is the fuel pressure. Key on? Engine running?

i forgot, did a wile ago. am thinking around 100 psi. but forgot. it was within specs according to hanes and chiltens manual at the time. what is standard for 99 4.0 ohv?