GMC Repair: 2002 Chevy Silverado 1500 5.3L, chevy silverado, air filtration

Question
It started like this.. When the air temp is cold(winter in South Dakota) I would let my truck warm up. It would run just fine. If I stoped at a store, or just shut my truck off for any reason, for any lenth of time, when I'd restart it, within a minute the idle would become rough, with very low rpms. When this would happen I would simply shut the truck off, restart it and it would idle fine and run okay. Now with recent warm up, with the temp outside like around twenty or so, first thing in the morning it would run like crap. Under these circumstances shuting the truck off and restarting it would not help in any way. The guy I got the truck from has plenty of automotive knowledge and seems to think its the IGNITION SWITCH. I've been looking online here and the common issues I've seen relate to the intake manifold or the throttle body. I really don't want to start replacing parts one after another like everyone else seems to do... I'm at a loss. Two weeks ago I drove outta town to a class, after the eight hours the truck did not start. I trailered it back to town, replaced the fuel pump, and solve That issue.. In other words, I've already put $350 into this truck this month. Please help me and my Chevy!!

Answer
sounds like an air filtration problem. Do you have a after market rechargable air filter? Mine did that when it got cold here as well. Excess moisture in the air. Check your fuel flow. Just check and see if your fuel flow looks good. Also try adding Heet moisture remover for your fuel tank, and a bottle of lucas as well.