My suburban cranks first try when cold but if engine warm or hot takes a long 2nd try please help I have tried to fix with changing fuel pump crank sensor and cam sensor

 

Please post your sub details- yr, motor etc

 

2008 5.3l

 

I had similar on our 1988 or 1994 Suburban, and bought a heat shield to put around it to keep out some engine heat.

I'd would clean all your electrical connections, and measure voltage across the battery terminals WHEN you try to crank it when the engine is warm/hot and not cranking. Post that voltage, should be above 9.6 volts then.