To start, in the last 18 months I've replaced all 4 O2 sensors 3 or 4 times each.

The van is a 1999 Chevrolet Express 1500 5.7L with 184,000 miles.
Even with codes it runs like a top and only uses less than a quart of oil between changes (and loses no coolant)

I bought the van 3 1/2 years ago and had check engine light on. 1 bad O2 sensor (I don't remember which one), I replaced it and all was good for about a year or so.
in the last year to year and half it started throwing codes for ALL the sensors.

I replaced them all with el cheapo generic sensors off Ebay. Codes came back within a couple weeks.
ok, I replaced them again with 4 Denso.
Codes came back again.
Alright, next time I used Bosch with the same results.
Finally I used OEM AC Delco sensors and now I'm getting codes for all 4 saying "no activity detected".
(before the codes would randomly say high/low voltage)

I'm ready to pull my hair out.

ANY and all help is much appreciated
(I'm on Soc Sec Disability and need the van to get to Dr appointments and can't afford to keep buying damned O2 sensors)

 

post the codes
are the codes for the heater elements...check the 02 heater fuses.

 

where do I find heather fuses?

 

Are they in the main fuse panel under the hood?

 

Right now I'm getting P0140 (no activity detected bank 1 sensor 2) P0160 ( no activity dectected bank 2 sensor 2)

 

do you have an scan tool that can read live data?
if yes, key on, engine off and check for bias voltage at the 02 sensors...should have 450mvolts.

 

does this mean anything to you because I can't make heads or tails out of it.

 

no, that information is not useful for diagnosing 02 sensors
you need to view the 02 sensor voltages. they should show the 450mv bias voltages in open loop operation and then start switching in closed loop.