there is a rattling coming from the header region on my gsr. not sure exactly where it is coming from but when my car is warming up i can hear it at exactly 1500 rpms (air idle control valve messed up so revs go up and down for a while but the noise is only heard when they pass over 1500). it seems to go away when the engine is hot, but if the car is just idling I can still hear it. basicly not sure if it may be top end, bottom end, or just something stupid I'm not seeing at the moment. I plan to rebuild the whole thing later on, but its also my daily at the moment and would like to get this fixed until then. thanks for your help guys.

 

Sounds like rod knock.

When the car is cold, the oil is thick. So maybe your oil pump is going out, or something along those lines. Try to diagnose it before it gets really bad.

 

well i am assuming since you have headers you do not have a heat shield anymore. so you probably have a rod knocking. if you dont want it to completely stop dont keep running it until you find out for sure.