Sometimes I can go outside and turn the key and it'll fire right up and idle but when you start driving and hold the gas for anymore than 45 seconds straight then it stalls out as soon as you let off, but if you hold the gas for 10 seconds or so it'll catch itself and start idling when you let off.. so after it stalls out you turn the key and it fires up and stalls instantly. I don't understand how one minute and it'll fire up and idle and then the next it stalls instantly.. I've replaced all the throttle body sensors including the iac, got a new fuel pump, cut the cat cause it was stopped up, replaced crankcase breather and pcv valve, I'm not sure what to try next.. when it does decide to idle you can hear alot of air being sucked from somewhere.. this problem started when I could tell the truck was surging and I changed the oil cause it needed it.. I'm not sure how the backfiring from the throttle body, the sucking sound, and all of that go together. Unplugging the brand new iac valve doesn't seem to affect idle much either.. it's just confusing.. could a bad throttle body cause all of this? Cause I cleaned it earlier and put it back on and it fires right up and drove it around and rpms weren't dropping as much when I came to a stop but I turned it off and tried to crank it back up and it won't idle again just stalls

 

Need to clean the throttle body really well, then reset the PCM, let it re-learn how to idle the motor.

Also, aftermarket IAC motors are not always as good as the mopar fellers, they just don't react quick enough......

 

Have you checked the plenum?