92 XJ dies on cold start up

My 92 XJ with a 4.0 has a problem when the engine is cold. It starts up fine then after coming down from the initial higher RPM it will die. If I start it over again or give it gas before it dies it will stay running. Once it is warm it runs fine. It also seems to back fire when cold when you give it gas. I have canged the idle motor, throttle position sensor, MAT sensor, temperature sensor, and the throttle body. The only things left are the exhaust sensor, crank position sensor and the fuel pump and filter. There are no engine error codes. Any ideas on what I should try next ?????
Dave

Last night on startup it took off and over revved. I shut it off before it got above 4000 RPMs. It did it twice then went back to running fine. I guess I'll try again on the throttle position sensor.

Check the vacume lines going to the MAP sensor. Mine was doing that and I just replaced them lame little plastic lines.

Coolant temp sensor good? It tells the ecm the engines cold ,so it will richen it up a little.......If it doesent know its cold it aint gonna run fat enough .....

My 96 did just about the same thing, it turned out to be junk in the IAC. Did you clean out the well, when you swapped out the IAC, is it possible the piston is catching on something?