I have this rattling sound coming from my engine. And it's not a rod knock or valve tick rattling sound. I know what both of those sound like and i'm sure it's not that. The strange thing is that when I first start the car it does it on and off every few seconds. After a little while, maybe like 20-30 seconds it stops and then does it only when I apply throttle but still comes on and off. I don't know why but I feel like the oil pump can be making this noise. I have absolutely no idea why I think this and i believe it may be completely wrong. It could just be that I'm paranoid about having a boned pump. I've head people talk about rattling sounds and knocking also. I don't know what knocking sounds like but i always thought it was like a pinging sound. If I had to describe the sound I would say it's like taking a thin flap of metal and making it vibrate really fast. Sorry for the lame description but thats what came to mind. I would give more detail but i'm currently removed from my supra because I'm at school and it's not. Anyway, this noise really scares me so I would appreciate any help.