2002 Chevy Silverado diagnose starting problem?

[Dave]

I've already replaced the starter two years ago, but here's what its doing now. When I turn the key, all power goes out and the idiot lights on the dash flicker. Then after about 5-10 seconds, the power comes back on and SOMETIMES it will turn over. Now here's the weird part, when it finally does start after one of these episodes, it will almost die (idle very very low) and I have to keep a foot on the gas to keep it running. If I can turn it off and restart it, it will idle fine. So my question is....what is causing the starting problem and after it starts, what is causing the low idle?
I have thought about a bad ground but am not sure
Thanks for any help!

 

[Tony T]

almost seems to be more than one problems . but first i would check all connections from the battery to the starter . take off both battery cables soak them and clean them with baking soda or coke or just very not water and a wire brush .. and before connecting the batter check you starter connections . make sure they are tight .. then put on the battery terminals .. try and start it if the same problem . have you had to charge the battery anytime this happens ? if not then that tells me the battery is good and the alt. is charger it when you get it started . if you have had to charge it this may fix it or you may have to check to see if it is charging . get it running and put a volt meter on the batter should be above 13.5 . if not alt . if good .. cold be a few thing . ignition switch is a possibility