i took each 02 sensor out and cleaned+re-installed.

also cleaned off the connections and wires

took the EGR off and cleaned that as well and sprayed intake cleaner into the MAF and TB.

reset codes, and re-scanned. now only get 91 and 44.

the exhaust is tight. why would my 02 sensor just all of a sudden go bad?

ive had a code in the past regaurding a bad fuel pump circuit and suddenly disappeared.

 

FYI..... I've had to re-replace brand new units after finding out they were producing (-) voltage. If they were bought less than a year ago, and you still have the invoice/ticket..... that one is still under warranty. To be 200% sure it's a bad O2 sensor, you can also swap them from sides, if a code 41 shows afterwards (failure code following the O2 suspect)...... that sensor is defective. LUK.

 

alrite heres the update..

i took the sensors out again and they were really black, as if i was running too rich.

cleaned em off and switched the sensors.

i was able to get some turns out of the collector bolts and all is tight.

still getting code 91 and 44, saying bank 1 is lean???

so ive pretty much ruled out a bad sensor and exhaust leak. next step would be to check the wiring but i dont even know where to begin.

how can i test if the sensor is switching/opening the circuit?

 

Start with....

 

ok i did the first test in the table and got .2-.3 volts on both sensors

i got confused on the other tests and wasnt sure how to create a vaccum leak with the key off.

i pulled all the plugs and every tip is white. car is running like dog crap.