Further update, Toyota had my vehicle all day and fitted the new camera; bloody thing did not work. So much for their diagnosis of an open circuit in the camera! Now I am told that I am going to have to remove all accessories out of the rear of the vehicle, so drawers, fridge and slide, battery and electronics that are all connected through to the main battery and solar system so that they can access the wiring in behind the side panels and drop the roof lining to further diagnose. Quoted me around $500 to remove all of these components so going to do myself and they are suspecting that the issue is going to be mine and not covered under warranty. The day after they fitted and removed the new camera, the rear vision started working for one day then died again so I am suspecting a wiring issue maybe through the tailgate or that as others have advised there is a faulty sensor under the passenger side dash that feeds into the infotainment system. I have mentionbed this sensor to Toyota on two occasions now and been fobbed off and not fault diagnosis undertaken that I am aware of.
Here we are at June 21. After another round of mechanics workshops, the full timing chain and all parts have been changed, the catalytic (upper inc. the manifold,) converter, oil pump. Still when started cold it's a loud clatter, that is irregular in loudness and frequency. As it warms that decreases in loudness and consistancy, but can still be hears. When at idle, I increase the rpm to around 1500-2000 rpm, the sound fades to nothing. Please help. The mechanics have not, but I'm 5k poorer.