I have a 2002 Silverado 5.3L V8 with about 130,000 miles on it. i replaced my battery 2 days ago, and later that day my truck wouldnt start on the first attempt. turn the key to off, try again and it started right up. it has been doing this since.. any idea whats wrong?

 

Sounds like it needs to go through a "relearn" process. This should improve over the next couple days and the more you drive it. If not let us know and we can start to help you diag it.