Maybe you hav more than just bad gas in the tank...
Pull the IAC out of the throtle body and see how its lookin.
If its full of thick black carbon, get some TB cleaner and clean the opening out good and let dry. Dont turn the end of the piece that comes out(the pental), it'll thow it outa wack!
I bet its full of carbon inside there and your intake .
Evn your EGR valve could be pluged or just not working
Also make double sure that thier isnt any Vacum lines disconnected or leaking.
And as gmack221 said, Thier is No Easy Button!