I tuned my sohc turbo civic a couple of months ago and everything was pretty close but still a little rich. about a week ago I had to change my o2 sensor, and ever since my car will sometimes stall when I down gear and have the clutch fully pushed in. the rpms just drop, no vibration or anything. after it will start up fine. tried adjusting the clutch nut but it still does it.

now my question is this do I need to re-tune after changing the o2. or is this another problem and what might it be.

Thanks in advance

 

no retune is needed after changing your o2 sensor....

 

what if you did your tunning to the old o2 and it was just about dead wouldn't it give you different readings

 

anyone have any Idea of what it might be

 

Tune it and leave it on open loop! If you tuned your maps well...your open loop will run better, then closed loop...