i have a 1998 ram 1500 with the 5.9l that has a small problem. when i start it up it will die, the only way to keep it running is to rev it. now this doesnt happen all the time. most of the time it starts up and keeps running just fine. no engine codes... could it be a bad pcv valve?

 

Try resetting your PCM first, but its most likely a TPS sensor

 

maybe tps-thottle position sensor (on drivers side of throttle body), but i'd go with IAC - idle air controller (on back side of throttle body) first. do a search for a million posts and be sure and clean out the well where the plunger fits as its prone to sticky build up.