well, i know i have two bad o2 sensors, and my truck runs fine, just really rich. like he said, and you can do this under the hood, by using the butterfly itself. get it started, and as its idling, go under the hood with the intake and all that stuff out and just hold the butterfly open very little. rev it alittle. and act as if you are in the truck, give it some gas, and then let it go back to idle but still hold it open very very little, if it does not do the whole spitting thing, then thats what it is.
how did you check the codes? cause it may have thrown a code but not a big enough one for the check engine or maints req light to come on. if you go to autozone and tell them you want to check your computer for codes. its free. and then they can also clear them for you.