Hi All,

I should have posted my update much sooner given all the advice I received from the friendly people here!

So, to recap...

My car was working just fine, purring like a cat...but very fumy!

My blackened oxygen sensors were replaced and suddenly she started to idle roughly and acceleration was a little rough.

What eventually turned out to be the fault was an existing MAF was not an XJR part but the non SC part. As soon as this was replaced the ECU quickly recalibrated and she has been running beautifully since.

Notes:

1. I was curious as to why the incorrect MAF sensor didn't cause a problem prior to the oxygen sensors being replaced. My mechanic told me that the old oxygen sensors were not working at all and therefore not sending any information back to the ECU so the incorrect MAF didn't cause a problem. Or something like that.
2. My car was missing a MAP sensor - looks like someone previously had broken it as it was "plugged" and taped up inside the engine bay. Having this reinstalled didn't seem to make much difference to the performance of my car.

 

Hi
It was the rough idle after an O2 sensor replacement.
Fixed now, replaced it again with a known genuine one and all is ok, idle is nice and smooth.

Thanks