Truck Forums - intermittent but severe idle problems

I am new to this forum thing and I don't know if this question has been asked already. I have recently received a 99 Ram 1500 with a 3.9 liter V6 and 5 speed. The truck was (to say the least) abused prior. When I got the truck the cat had been cut out and the back O2 sensor had been cut ahead of the connector. While driving, the first 15 minutes are fine, but after 15 minutes pulling up to a stop light is embrassing. The truck will cough, gag, spit and sputter unless I redline it and slip the clutch to get it going. Once moving it drives fine. And it doesn't do it at all stop lights. When it does do it you can hear massive amounts of air getting sucked in but the butterflys don't move. I've run a code reader on it myself and had a shop run a hand held diagnostic, but no codes. Only thing that seemed odd was that the reading from the back O2 sensor never changed (it was repaired from being cut by soldering the the new sensor to the wiring harness). I've also changed the front O2 sensor, Idle Control Motor, Cat Converter, cleaned the throttle body with intake cleaner spray. I've checked for vacuum leaks and for proper voltage at all the sensors. Does ANYONE have ANY IDEA what might be going on. I have no idea besides for changing the MAP and TPS and finally the computer. TPS isn't expensive but the MAP is $80 and the computer I can only guess. If anyone can help PLEASE post any suggestions. Thanks.