My Nissan Sentra was acting up when the engine was between cold and hot doing all kinds of funny things.
Changed my idle air control valve which helped a bit. There is three other things it could have been too. The car's computer, a valve that opens like a shutter when the car starts to warm up and thermo sensor in the coolant line.
also possibly the o2 sensor but the car wasn't showing a code.
well on chance I ordered a direct Japanese replacement for my o2 sensor to swap out the Bosh one I had installed ages and ages ago.
First thing I noticed is the replacement is a lot longer with a lot of large ports unlike the puny Bosh sensor with it's tiny ports and a short stem.
also that the Bosh sensor was half plugged with car emissions over the years I had it in.
Not a hard thing to do if you saw how tiny the inlets were to the sensor.
Got the old one out and the new one in without to much trouble thankfully
wonder what a Nissan dealer would have charged for this very easy replacement ?
What a difference it made !
A world of difference
It isn't absolute perfect because of the cars age and other sensors mind you but I can honestly say it's a 200 % difference to what it had been.
car has regained all it's old power and then some and idles FAR BETTER
I wasn't going to change the 02 sensor out because it wasn't throwing codes as some car forum members said
BUT apparently the 02 sensor needn't throw any codes before it gets pretty crappy !
Moral of the story change your 02 sensors out even when they don't throw any codes
You will be glad you did.