Can't figure this out, really need help.

I've been working on my 88 5.0. When I start it, it runs good but as soon as I let off the clutch it stalls. Nothing I do stops it. It has never done this before and just started the other day. Is there some kind of adjustment with the saftey switch or something that may have gotten out of wake. Again, I start it with the clutch to the floor and as soon as I start to let off it stalls. I can keep on the gas and nothing helps, just dies. Any help would be appreciated, thanks.

Well, I unhooked the battery, hooked it back up. Car started good, let off the clutch and it did not stall. Seems like some kind of a saftey feature. The car will start and run cold but when it warms up it wants to stall and eventually will and will not restart until it cools down. I believe the trouble may be coming from my dizzy or TFI module, since the saftey switch is wired directly to the module. Going to test the module, or buy a new one if they are cheap enough and see what happens. Thanks alot for the input guys. I would like any other suggestions or comments if any are available.