Ever since the I-DTEC engine was introduced there were some unfavourable remarks being made by owners and the journalist regarding the diesely knock. Some took this noise in their stride some were suggesting this so called characteristic as a backward step from the refined I-CTDI. Honda did take this feedback on and have made continuous improvements in this area ever since it arrival in 2008 , now in 2011 and with the arrival of model revision model 2012 this noise is now lower and at par with the outgoing I-CTDI engine. However this thread is for owners who have purchased or looking to purchase a 8th Generation and to educate them please ask relevant questions if these updates have been applied to your car. so what do you look out for ? Symptom Combustion noise between 1500rpm and 2000rpm whilst on light throttle. The noise is most noticeable when the engine is cold engine and when the air conditioning is switched on. Cause Initial condition variation of fuel injector injection hole causing a varying pilot injection volume and direction. The Fix Updated software for more precise control of initial injector quantity variation during pilot injection phase. Honda dealers are being sent regular updates via DVD's which are deployed via the HDS tablets and HIM.. TIP For all new second hand owners owners planning to buy a I-DTEC. You can request any franchised Honda dealer to look up MARIS (A Honda internet portal ) to see if your car VIN has had any warranty or any product updates applied. if you haven't then you may need to negotiate that as part of your sale, as cars outside warranty period may be charged for these updates. This is even more vital is you are buying a lease car which has never seen a Honda dealer for its routine service.