I have two 2000 silverados both with same problem. One has a 5.3L(139,000mi) and other 4.8L(104,000mi). They are both hard to get started. You have to crankat least 3 or 4 times to get them started. This happens in all conditions just about everytime. Sometimes tapping the gas a bit helps. Once started theyrun like new no problems, loss of power, hesitating, anything.They are very well maintained, good synthetic fluids, new filters, new wires and plugs, new pcv valves, run fuel system cleaner when oil is
changed, the works. The 4.8 has had these problems for about 40,000mi and the 5.3 is very recent. Please help.

 

Well it looks like they both started having problems at around the same mileage, i would say weak battery, but if that was it, the one would not have gone another 40,000 mi. Maybe the starters start getting weak around 100,000mi? Just a guess...