I just got a 03 disco II and it is perfect but when I started it the other day it started making a slight tapping noise and then it went away. but today I started it and the same thing happened but when I pushed the gas pedal the noise got louder and sounded like a tapping noise almost as if the timing chain is loose but if I let off the gas it gets a little more quite could someone please help me with this cause I would really like to fix this problem?