[need4speed420]

i know exactly whats wrong with it. you have a vacum leak going into the throttle body, i had one also, it costs about $15 to fix it......... theres a hose going into the throttle body, it is probably what is leaking the hissing sound is air being ucked into the throttle body....... get some propane, and let it leak out of a hose, put the hose around the throttle body and see if the idleing get better in omeplaces