After letting off the accelerator, it tries to stall?

Yes the mil has been on, mainly because my catalytic converter was removed. I had checked my alternator, map and throttle position sensor yesterday and they all seemed to be fine. Battery voltage was around 13 volts and map and throttle voltages were close to the 5 volt references. My old instructor said it could be some sort of rev limiter to where it keeps the truck from revving too high but they have it set very low

Well the codes that I can remember is that my manifold absolute pressure circuit is high and there is another code relating to my manifold circuit. Okay so what do you mean I could be getting all the wrong readings without my cat converter? I do know that an issue such as a clogged cat can result in a no start condition. And I did check my IAC. On wire 1 and 4 connected to a vantage, my second window was getting somewhat of a glitch on the top corner of the digital signal and on my # 2 and 3 wire I got no reading whatsoever. I also figured out that my fuel injectors on the inductive kick are getting less than 14 volts.

I havent yet but I will. I see now, im going to replace the map and hopefully it'll all work out as far as the dying. Gracias, I'll let you know how it runs after.