Dear Forum,
This may well be one for JagV8?
The first upload is what (with small variations) my FT's have been for a very long time.
Sudenly, my STFT's periodically jump off a cliff, so my LTFT's Climb one to compensate, then normality is restored for a while...
NO CODES...Any ideas, please?





My Jaguar is running beautifully?

 

single digit ltft

ignore and pretend it doesn’t exist. a dying wideband will do this type of stuff

 

Xalty, thanks for your reply; just out of interest, what IS a 'Dying Wideband', please?

 

One on its way out... failing somewhat... (pining for the fjords? no, that's an ex-wideband LOL)

Each sensor 1 (i.e. upstream) is a wideband aka linear sensor. They're better because the PCM can tune fuelling faster and more accurately - but cost a bit more. Newer tech than the old kind (which are commonly used for downstream as they're good enough for there).

 

Esray: You don't tell us if this is just idling or while driving. Either way, what you're seeing is well within normal as indicated by the lack of codes. Also remember that net fuel trim is LT + ST so it looks like your worst case is really about -6. My advice is to stop watching your FT graphs and enjoy your car.

Best Regards
Jeff

 

Thanks JagV8, so just keep a weather eye out for an upstream O2 sensor shuffling off its mortal coil?

 

Thanks Jeff,
It was just that my trims have been so consistent for nearly six years and all of a sudden...?
Nevertheless, you are right...My trims have now returned to normal...Sometimes some of us on this forum can be guilty of over analysing everything!

 

Enjoy... nothing looks to be pushing up daisies.