Interesting Inconvience

[Abella]

So i think i have pretty bad luck! i bought my 2002 mustang v6 in october and since i have had to put a new clutch, altenator, and all those other expensive parts well after i got the altenator and idler pully replaced i started noticing a problem where i would be going about 1200 rpm and would let off the gas the tiniest bit and my car would die, unfortunately i dont usually just have a code reader sitting in the passenger side seat to read the code and it is not usually dying in a convient place so i just turn her back on and she fire right up all nice and pretty and the code goes away. when i plug in the code reader after words it comes up with nothing. so im thinking that the throttle plate, IAC, and MAF need to be cleaned off but if that doesnt work i need some new ideas of what it could be. it also idles up and down at stop lights in netural so if im just sitting there at a light it will drop from about a grand to 500 and idle rear rough for like a second and a half then shoot right back up to 1000 i dont know if they are related but that is really just a problem that i want fixed and i also it happened to me about ten minutes ago and when i turned on my car it made a real weird noise. when i poped the hood the brand new serp belt was shreaded so idk whats going on or if these are related but i really want to stop going though these belts like they are water and maybe just maybe get my car to stop idleing weird. im thinking the egr might be involved but im not sure