Put in new O2's, Pulled Codes

[DRock9]

I put in one new O2 sensor to fix a backfiring problem when cold, and maybe to fix my engine breaking up at high RPM under load. It didn't fix the problem so I bought another one and put it in, before running my car at all I pulled the codes KOEO/KEOR and it gave me a bunch of codes that I have never seen before.

I drove about 150 miles since then and I just pulled them again, I got an 11 for KOER and a 31 for KOEO...but all my other codes dissapeared.

I used to be getting a code 96 but it is gone, used to be getting a 41/91 but it is gone.

Do O2 sensors need to be broken in to start working right? I noticed last night and the day before when I put them in after letting it sit for a while and starting it up, if I got on it hard right away it would fall on its face and sound like it was going to die/really bad misfiring so I let off right away.

I am going to install a new fuel pump and hopefully that fixes my problems, other than that I am going to check my vacuum to see what I am getting.

Thanks!

 

[Jaswir]

i had a simular problem and it turned out to be my MAF sensor... but it did pull the code so i dont think thats ur prob


i would put a new fuel pressure gauge on before doing the fuel pump....

 

[jrichker]

CODE: 31 (KOEO) - EVP circuit below minimum voltage. Vref (5 volt reference voltage supplied by the computer) missing or broken wire or bad connection in circuit. Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white wire on the TPS or MAP sensor located on the firewall near the center of the car. Use the black/white wire for the ground for the DVM.
With the sensor removed from the EGR and still connected, press the plunger and watch the voltage change on the brown/lt green wire. Pull the passenger side kick panel and measure the voltage at the computer. You will need to remove the plastic cover over the wires and probe them from the backside. A safety pin may prove very useful for this task. Use pin 27, EVR input (brown/lt green wire) and pin 46, signal ground (black/white wire) to measure the voltage. The orange/white wire is Vref and should always be 5 volts -/+ .25 volt. Be sure to measure Vref at the EGR sensor to rule out any broken wires or bad connections.

 

[DRock9]

I checked the voltage at the TPS and it is 4.96v, the tps is at .93v...I had it set at .99v but my idle was waaaay too low.

I just pulled the codes again and KOEO was the same 31...but this time KOER was 12, 21, 41 AND 91!

I just put in new O2 sensors so does the 41/91 codes mean I have a vac leak somewhere? My idle is steady, doesn't move...however when I am coasting to a stop and put it into neutral my idle stays high until I finally stop then it drops to the regular idle.