Dads 02 Dmax went to have some injecter work done a few months ago and ever since it came back it mackes a nasty chattering sound when it is pulling hard. It has a duramaximizer and 4" exhaust but it started the chatter thing before the exhaust was installed. It has much less power than before but appears normal otherwise. Warranty is out so we dont want to pay the dealership to go expirament with it.