Hello Everyone, my Z has a rattle. It only happens when I put it under load. The oil is good and it don't run hot also it does not do it any other time. But I have noticed it uses oil a little bit. There is no leaks I have washed the under side of the engine and ran it down the raid and parked it and crawled unde it and watched for leaks. It sounds like a valve rattling but I don't know. Does anyone know?

 

Check fuel pressure while engine under load.

 

Try changing fuel grades as it could be spark knock.. How old are the plugs?