Engine Rattle between 1000 - 1500 RPM
 

I have an issue with my revs dropping and my engine potentially dying with my MAF sensor plugged in. The MAF is good but now I've unplugged it for the time being in order to be able to drive the car, which I can with it unplugged.

But now I'm getting a rattling noise between 1000 - 1500 rpm. Until I get the MAF sensor/rev issue fixed, what is this rattling noise and how do I spot it?