firebird dies after 10 sec. won't stay idleing

I have a 1991 pontiac firebird, 5.0L 305 Tuned Port Injection. It starts up fine and then putters out and dies. However, when I rev it it works fine. Also when I unplug the wire going to the IAC motor it idles high at 1400 rpm and idles smooth, when I plug it in it putters out then dies. I've replaced; o2 sensor, checked all vacuum lines, replaced IAC motor, check engine light works but does not come on while running, so I don't think it's a sensor. Can't figure out why it won't stay idleing!!!

Has the TPS gotten wet recently?

possibly, yeah hood was off for a while but covered it with tarp... could have gotten wet.

I would repalce it. They don't like moisture at all and often times, will not set a code.

Alright I will, thanks man...