1994 Dodge Intrepid won't run

Engine Mechanical problem
1994 Dodge Intrepid 6 cyl Front Wheel Drive Automatic

i have an intrepid with the 3.3l engine it won't stay running without some help, I have to press down on the accelerator to get it to start and I have to feather it until it warms up a little, then I can use the seat and a rod to maintain running at aprox. 2000-2200 rpm while I check things even at that rpm the exhaust is black, I have replaced the idle air solenoid, replaced the upper intake gaskets an cleane the throttle blae and passages also checked vacume lines for leaks and still have the problem. I am thinking that it could be a couple of things 1. Map sensor 2. Tps 3. Oxygen sensors. Any help you can provide would be greatly appreciated
thanks sam