Chevrolet Repair: Poor Starting and Heater repair, chevy siverado, mechanical abilities

Question
Morning BSB,
Have two questions for you about my Chevy. It is a 98 Chevy Siverado, Z-71, Vortek 350.
1st, at random times, it gives me fits when starting, example: I ran to the store the other day, the truck started fine when I left the house, got to the store, was inside for a few minutes, came out and all it would do was turn over, it would sputter every now and then, but would stall, after about 10 minutes of attempts, it finally started. This does not always happen, sometimes it is fine with no problems, other days, it throws this curveball at me.
2nd, about 2 weeks ago, I had to replace the Alt, it dies and in the process, killed my battery, so both items are brand new. I am not sure if it was coincidental, but, now, my heater will not work, it still blows out air, but only cold air. The A/C still works fine, but no heat.
 This is my first Chevy and even more importantly, though I have fair mechanical abilities, my knowledge of these types of things is limited. So detail would be a good thing.
 Thanks for your time.
  Shayne

Answer
The starting problem is probably your fuel regulator.  The ac problem would have to be diagnosed.  I do this sight to help people out and my honest advice is bring it in and pay to have it diagnosed at the dealer and then make the choice if you want to do the reccommended repairs suggested or have them do it.