Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
I have been working on a suzuki CIAZ 2015 (Map type) ,, showing on the LTFT
- 17% without saving a fault code and the engine keep misfiring and running up normal, the O2 sensors had passed the lean test when pulling a vacuum hose and rich test when spraying fuel through throttle , Map sensor giving reading 49KPA at idle
But the non sense which happened to me that the car runs perfectly when unplugging the O2 sensor !!!!!! And LTFT tends to zero !!
Any explanation ! I'm getting crazy !
Note : the car has just finished a head gasket job .
Your 02 is oscillating normally, between 1 and 9mv is normal. Your engine is running rich, getting too much fuel so the pcm is taking away fuel. By unplugging the 02 you are taking away the 02 data from the pcm so it goes into open loop. You showed that the 02 is responding via vacuum leak and fuel, so the 02 seems Ok but as Tutti57 said, it could be contaminated with coolant.
You say the idle is rough. Is it also high?
"an open mind let's knowledge flow in and wisdom flow out for a man who has neither never listens to those who have both".
Being wrong doesn't bother me, it's being right and not understanding why that does
I believe Paul said he is happy when he sees .2v to .8v when switching. You won't be able to tell frequency without a scope. I think the ECM is pretty good at detecting a slow response, so follow scannerjohn here.
I'd suggest rechecking that reading with a hot engine at idle with no loads on.