HELP!!!

My throttle cable got stuck today for the second time in a week!!! I was on the freeway when I floored it and the throttle wouldn't release. The pedal itself was fine, it popped right back up, but the car just kept accelerating. When I put it into neutral, it just revved all the way to redline. I pulled over on the shoulder and killed the engine. The first time this happened (on a different day), I turned it back on and it worked fine. Today, I turned it back on and the car continued revving like a crazy b*tch. I finally got it towed and by the time my mechanic started it up, it was working fine. This only started happening after I got my nitrous installed. It's set up to spray at full throttle and that's when it gets stuck, so I figure maybe they messed up the install? My mechanic disconnected the cruise control cable as a precaution, cuz he said it might be that, but I doubt it. I haven't tried the NOS out yet cuz the bottle I got was defective so I sent it back, but if i do spray and the throttle gets stuck, I'M SCREWED. I'm pretty sure something in the engine will explode viscious with nitrous and a stuck throttle. If anyone knows what this could be, any input is appreciated. Sorry about the long post, but I wanted to give all the info I could.

-GR