Hi.
I looked at this for a garage, it came in with a reported misfire, they previously fitted a new front O2 sensor.
Vehicle reported random misfire and fuel trim limits exceeded.
Engine was running in open loop. Ltf was about -3.5%
I stored and cleared the codes and watched the o2 sensors and noticed every 4 secs or so there was a 65v peak seen on the front sensor trace?
I checked in EOBD but couldnt see it? I hooked up a modis and found the same result.
I checked an earlier 25 and found it working correctly.
I swapped over the coils and the front O2 sensor but with no change,
I havnt proved this is why is is throwing the system into open loop and /or causing the misfire, but it seems like a probable clue, so I went away to think about it.
Have done so but havnt come up with any ideas yet.
Anybody seen this before?
Thanks.