i've been hearing this for some time now but never thought much about it. Sometimes (specially when first time in the morning) when i turn the key to on position, and i hear the fuel pump making the whiirrrrr/hmmm sound, i hear a rattle from the engine. its a short rattling sound for like 2 seconds, its like something loose moving around. and i been hearing it since i changed the spark plugs.

The car's been starting rough too lately. but after starting the engine runs perfect. no missing or anything.

 

does the rattle make noises in time or are they sporadic?

i.e. * * * * * compared to
* ** * *** **

just think of the * as a tick per *

 

no sequence....just sporadic...but very short. sounds like something loose being bounced around inside while something else is moving beside it

 

only thing i can think of is the fuel system doing something weird or there's a relay up there that is freaking out. i'm not sure what else could be making noises since the engine isn't even running.

 

Why don't you get someone else to turn the ignition on, while you stick your head in the engine bay and try to narrow down exactly where the sound is coming from. It has to be something electrical or fuel related since the car isn't even running. Do you have ABS? Maybe it's the ABS motor doing a self check?

 

you'd be laughing but it might be a stuck relay for something (not relay itself by all means) if it is freezing outside like -35C in Ontario.
headlights relay was stuck on my car this morning

 

does the distributor rotor spin as well to find the crank shaft position? when key is turned to ON?

 

nope, distributor is mechanically ran off of the camshaft. the rotor won't move without the engine.