completely lost need help

Ok my car keeps dying at random and I have found that the problem is a signal being sent to the throttle body. It will do this with the engine off as well I can just turn the key on and you can hear the clicking noise after a few moments from the throttle body. I am assuming that this is a sensor problem but I can't even begin to guess which sensor could be causing it. Also the car is a 92 3000gt and for some reason they must have skipped that car when making code readers because I have found none that are compatible. I took it to a local shop today and asked them to put it on their diagnostic machine but as the trend seems to go they said that they couldn't hook it up. So I am running out of patience and ideas if anyone could please give me a clue I would greatly appriciate it. Thanks