hey, whats up.. the things that your describing are basicaly the same things that i delt with.. im farely new at this but just for shit and giggles i let you know what i went through...., i had gone to the track.. and im not going to lie, i beat the hell of my 04'... you know, to see what it had.. after about six visits or so to the dealer we had discovered that since had so called "doged" it out, that the motor was lifting a good amount and had snaped what they called the T.P.S. ground wire, from the motor lifting.. ask them to play with that connection which is located by the throttle body.. they will know what you are talking about.. and see what they come up with... after they went that route with mine everything was back to normal... i had the same hissing sound.. my advise is take off the blow off plate from mopar.. if indeed the plate is what your talking about, because from research i have come across i here that plates are known for sometimes being defective.. how you ask... I HAVE KNOW IDEA! but took mine off just in case.. i really dont need anything myself until i exceed 300+hsp... hope i could help.... let me know the out come, if you dont mind... Thanks, Cuz. :thumbsup: