vs v8 series 3 commodore ute

[Thorney355]

hi my vs series 3 v8 commodore ute feels under powered has new fuel pump new adjustable fuel regulator. fuel pressure is spot on. has new air flow meter plugs leads dizzy cap rotor button. throttle body sensors are all new. thought it maybe oxygen sensor so replaced it with
bosch 0258 005 703 witch is direct replacement for AC Delco AFS75. now the problem is still under powered and when on the highway about 2000rpm for about 10 minutes throws engine light up for oxygen sensor but everytime check for problems reset fault code does it again but it will change from lean fault to rich fault all the wiring harness is ok has good earths to oxygen sensor thought it might be vacuum leak as series 3 utes run A/F meter no vacuum leaks. had ecu checked and its fine even swapped it with my mates series 3 ute made no difference. im out of ideas any suggestions would be great thanks

 

[Zeke Topanaga]

Was it fine before you changed the fuel pump.
Oxygen sensor did not have oil on it when you put it in, even oil in your fuel will destroy it in 20KM a mate would run out of fuel driving home from riding our bikes and he would top it up with his CR500 fuel at 50:1 and that was it, he destroyed the sensor in just 20KM I said not to do it but he did not believe me thinking it's only 20KM but the moron did it again and the same thing happened again.

 

[EYY]

Mine was doing the same - for the first 5-10 minutes it was running well, then would run extremely lean. So much that it was almost undriveable - hills became a big problem.

When this happened there was no reading from the sensor at all. Tried replacing the sensor and no change.

Then I replaced it with a 2 wire sensor and replaced all the o2 wiring and it's been good ever since (got it sorted 3 weeks ago or so)