I had a very similiar problem. As soon as i turned the key to the on position You could hear the imrc box snap open the secon. and they wouldnt close untill i turned the motor off. I took the box apart everything looked okay. still didnt work. So i took and old box from a local friend(thanks scott)he had problems with the box not opening(typical prob). Anyways i thought id put his box in my car just so i could bye some time. Well when i put in his old box i moved it to were the filter is on the intake. and i have never had a prob since. and this was over a year ago.
So the moral of the story is. You prob need a new box and cable. get it from a junk yard. and just move the new box to somewere it doesnt get so damn hot.
O and good luck

98 csvt t-red.. sho-shop intake, b&m, fidanza, spec1 clutch, Torsen, DMD,optimized Y& TB, Brullen, rear strut bar,h&r's,17" konig traffik's. "I say what I mean and I do what i say"