1999 yukon sle cranks but won't fire. on 1999 GMC Yukon

my 1999 yukon sle after running the vehicle about an hour and park it when i go to restart it it just cranks and will not fire. let it sit a day and try it it will start. i have changed all plugs cap and rotor fuel filter exhaust (catalitic convertor) and i am getting fuel and spark . i also changed the 02 sensors as well . vehicle sometimes will go for a few days sometimes before it starts doing this again . it seems to have a mind of its own i am at a loss

Asked by for the 1999 GMC Yukon
I have some what the same problem on my 96 Yukon SLT. It cranks but just makes a somewhat muffled sound and wont start but only certain days or times during the day, but it recently got worst it wouldn't start at all one day i keep trying hopping it Started when a buddy showed up and told me it was the starter not getting enough charge so i messed with it tighten the wires and it started. I haven't replaced it due to time and money but i can make it start every time by just barely turning the key halve way and letting go as soon i hear the first crank. Its weird but it works and if i turn the key normally and have it cranking it wont start for nothing.Hope this helps you