FYI , thats not a belt noise . Its more metal hitting metal.More a tappet noise tham anything else. How many Ks has the car done? Did the sound start after you got the car ? I know you mentioned the oil is topped up but what colour is the oil ? If its too dark change that first and then try running PULP to see if the noise dies down a bit. You will always hear these noises close to the rocket cover but it shouldnt be as loud as yours. The ZZE's cant be Tuned (like adjusting points etc) so i doubt much will show up in the Diagnostics. As for driving the car in the meantime , you shouldnt have any problems but try keeping the Revs under the red line. ;) As for the fuel issue , i dont think its directly related to the noise (happy to be corrected if wrong). Depending on the KM's travelled it might require a Injector clean.(Previous owners sometimes can have poor fuel choice) And as mentioned before if your oil is dark then this will be or could be causing both your problems. Car has done just under 120,000kms, and not sure when the sound started, I've noticed it in the last few days, could've been there before though, not entirely sure. The oil is a normal golden syrupy sorta colour, oil straight utta the container colour. Wish it was the oil, but yeah... hopefully since I'm taking it to sydney city toyota they'll know exactly whats wrong and fix it