**UPDATE** Tested the temp sensor and it was within spec. I also changed the 02 sensor and it has reduced the roughness of my idle by 80-90%, it is now starting to feel like a MB! The remaining idle rumble is pretty much identical in frequency to the original rumble prior to swapping out the 02 sensor much much, much less significant. I am guessing it was over fuelling and now i need to chase the final reminants of the rumble but for the moment i am very satisfied.