Picked up a Mazda5 GT Auto in April and currently have just over 5000km on it.
Since day 1, I've heard engine knocking at around 4000rpm+, especially on load like on a grade. Initially, I was told by the dealership that the engine needs a few thousand km's to break in and the sound will go away.
Well, I brought it into the dealership yesterday and of course, the technician couldn't hear anything. So, I took the technician on a ride and sure enough, we both heard it. He asked whether I use good gas... I've put in Sunoco/Pioneer gas and 2 tanks of PetroCanada 87 octane.
So his immediate suggestion was to put a tank of higher octane fuel in and then it should go away.
In the meantime, the technician's going to look at any Mazda bulletins...
Does anybody have any thoughts about this?