i have a 98 xk8 ... when the engine is cold the car starts fine ... sometimes when the engine is hot it will not turn over at all ... complete silence ... if i open the hood and wait for 5-10 minutes and try to start it it usually starts fine ... any suggestions??? ... i have had the battery checked, the main electrical cable replaced, and moved all the relays ... no change

 

Sounds like a classic heat soak issue and the only way I know to diagnose the issue is to let the engine idle till hot and when you get an no start, start by checking voltage to the starter and work your way back to the ignition switch.