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I am just wondering on others thoughts about this idea I have.

Using TunerPro logs, i have noticed this and I am thinking it could be significant sign for either a no spark or a poor closing injector.

While in Open Loop, and the O2 sensors are both holding around 20mv (Lean Condition). There are two or three significant spikes to around 600mv (RICH) in one O2 sensor (mine is the RHS). This occurred on rapid decel to 0% TPS.
This makes me think that there is either too much fuel still getting in to the cylinders (for mine being the RHS) from maybe a sticky or dirty injector. OR a no spark condition also on that side of the engine.

Would that be a logical diagnosis? Any other thoughts on that logic?

Also, O2 sensors that are not in phase, is that normal? Like 180deg out of phase at times.

Could you post the log?

Is a screen shot ok?

Another screenshot, same log, later on.

No spark will always read lean even if there is lots of fuel as it is not burnt.


Could just be manifold fuel, but is odd how it's only one side. But that said all my engines get a rich spike on close throttle before going lean due to manifold fuel being suddenly boiled off due to the hard vacuum.

Ok, thanks for that feedback.
I am suspecting injectors, which I know are a mix of 3 unknown history ones and 3 originals. Yes, originals from at least 2004 when i got the car, with now 506,000km and the third motor they're on.