4 Wheel Drive/SUVs: engine often stalls when starting, sierra 4x4, air control valve

Question
Matt, I have a 2000 GMC Sierra 4x4 with the 5.3L Vortec engine.  It stalls often when I try to start it.  It seems to start up just fine when the engine is cold, but as I'm running around town, it often stalls or almost stalls(rpms drop), or turns over but doesn't start at all.  I find I have to give it a little gas to get it going.  Any idea what it could be?  The check engine light is on but the only code that comes up is for a engine knock sensor.  Is this related?  Thanks in advance for a response.

Answer
Steve,

usually if you can put your foot on the gas petal and it runs fine until you let off and it dies, it is the idle air control solenoid located on your throttle body. GM usually does a trottle body cleaning as a part of a scheduled maintenance interval for example the 10-20-3- thousand mile services. I would start by pulling the air itake pipe off of the throttle body and see if it is gummed up or not. clean it and give it a try. if it still gives trouble it may be in tou idla air control valve and they can usually be cleaned as well

Thanks for the question
Matt