Long Term Fuel Trim at -21,1%
I have a Nissan March(Micra in Europe) 2014 1.6L (4 cylinder naturally aspirated FlexFuel engine), i bought a Creater 3001 Scan Tool and upon checking the data i noticed that LONGFT1 is -21.1% SHRTFT is ok, it does not go above +-10% and after warm up at steady speeds is 0.0%. Car runs fine should i worried about it?
LTFT indicates the car is running rich, check for leaking injectors or possible bad fuel pressure regulator. You say the car is running fine, I would drive the car and watch the data. Compare the data when the car is cold vs hot.....
If it’s running that rich and you do nothing, you’ll ruin the converter.